This is a plot bunny that bit. Hard. It's totally AU and therefore mostly completely out of character.

I am actively looking for a co-writer (or five) for this one, I'm considering going totally off-canon after this (I mean, this version of Sheldon wouldn't break into anyone's apartment to clean, but some of the later episodes might work) or picking and choosing bits of episodes to integrate into this story.

Anyway, reviews are love, and I hope you all enjoy it!

The Role Reversal Hypothesis

"Lee, we are not donating sperm."

"Come on, I really want T-1 bandwith in the apartment."

"Sheldon..."

"Oh, dammit, don't fracking call me that! Fine, I'll pick up a couple of extra shifts at the restaurant instead. The manager keeps asking me to tend bar on Saturdays, I guess I can do that."

"You know damn well that your tips from two Saturdays a month will more than pay for the upgrade."

Leonard managed to drag his lanky roommate away from the message board in the hallway of the university they both worked in, attempting to divert his attention away from the flyer advertising the high-IQ sperm bank downtown.

Leonard Hofstadter was an experimental physicist at CalTech, having acquired his PhD against his mothers' wishes, an act of defiance that had turned into a career that he'd been surprised to find both enjoyable and fulfilling. Living in California was mostly a bonus, keeping him a trans-continental flight away from his overbearing mother and allowing him to indulge in various pastimes, including surfing, that he'd never been able to fully engage in while living in New Jersey.

Sheldon 'Call me Lee or I'll sucker-punch you' Cooper was his roommate, having made his way through college at CalTech on a football scholarship and been recruited directly into the physics department after a devastating injury to his achilles tendon just weeks after he'd completed his own PhD. Leonard had moved in with him not long after the injury, when his previous roommate had left in disgust at Lee's downward spiral into depression and the constant, unreasonable demands that the once-was-a-star football player was making on his time.

Two of the smartest guys in the university were also universally adored by most of the grad students, and each cashed in on it often enough that there were warnings about '5A, 2311 Los Robles' posted in more than one of the ladies' bathrooms on campus. Their reputations, unfortunately, preceded them in a lot of instances, but that didn't stop them from each dating a series of women.

The pair of them walked up the stairs towards their apartment, Lee shooting Leonard his usual, patented, 'Glare of Death' as they passed the omnipresent OUT OF ORDER sign on the elevator door, and Leonard, as usual, ignored it. Admittedly, it was technically his fault that the elevator no longer worked, but Lee was hardly free from blame. It had been his idea, or rather, his quick-thinking, that had led to the unstable rocket fuel being dumped into the elevator shaft, but it had been Leonard's incorrect equations that had caused it to be unstable in the first place.

It wasn't until they got to the fourth floor that they noticed anything amiss.

The door of the apartment opposite theirs was open, and there was a blonde woman visible through the aperture, wiping a straggly lock of hair out of her face as she set a large box down on the kitchen counter.

Leonard waggled his eyebrows at Lee, who rolled his eyes before commenting.

"New neighbor."

"Significant improvement over the old neighbor." Leonard countered, eyeing the girl extracting colorful crockery from a box labelled 'KITCHEN'.

"A 200-pound transvestite with a skin condition? Yeah, she is." Lee told him, stooping down to pick up one of the boxes from the hallway before stepping in front of Leonard to stick his head through the door.

"Afternoon, miss."

The blonde almost jumped over the counter, startled by his voice.

"Hi." she turned to face the two men hovering on her threshold, her voice low and timid.

Taking this as an invitation, Lee stepped into the apartment and placed the box on the floor in the middle of the mostly-empty apartment.

"Hi there. I'm Lee, this is my roommate Leonard." he extended his hand towards their new neighbor and she rounded the counter, eyes downcast, before catching his hand and shaking it quickly, withdrawing her fingers as quickly as was polite and wiping her hand on her jean shorts.

"Penny. Penny Olson. Soon to be Doctor Penny Olson, but I have to finish my PhD, first."

"Great to meet you. Did you need help with anything else?" Lee asked, the Southern Gentleman that his mother and Mee-maw had drummed into him his entire life kicking in before he could stop himself.

"Uh, well, there's a few boxes in the hall, thanks..."

Lee stepped back past Leonard and picked up another box, toting it past his static roommate and into the kitchen of the small space. Leonard followed his progress, before turning his attention back to the new neighbor.

"We've got Indian food, if you haven't had lunch, yet?" Leonard asked, holding up the brown paper bag he'd been toting up the stairs.

"Lunch would be great, I haven't had Indian food, yet, this week."

"Well, come on over, we live across the hall." Lee gestured towards Penny's still open door, and she paused for a moment, before nodding.

"That would be agreeable, although I can only stay for half an hour, I need to contact the building manager, my shower isn't working and I've been hauling things up these stairs all morning, I'm afraid I might be rather pungent company."

"You can use our shower." Leonard volunteered.

"She can?" Lee asked, one eyebrow raised, trying to convey something to Leonard without speaking. He failed, miserably.

"Yes, she can." Leonard told him, nodding to emphasize his point.

"Oh, I don't know if that would be appropriate, I only just met you..." Penny mused.

"Think of it as a welcome-to-the-building present." Leonard told her.

"I can call Ralph for you, I've got him on speed-dial." Lee put in, winding around Penny and Leonard, still sort of paused in the doorway. He picked up Penny's ironing board and bought it into the apartment, leaning it against the wall next to her bedroom door.

"Alright, then. You have clean towels?" Leonard nodded. "And you're certain there will be enough food for the three of us if I join you?"

"God, yes. Lee always orders way too much from Mumbai Palace." Leonard told her, stepping back from the doorway to allow their new neighbor enough space to step past him, and Lee, showing off the stealth skills that had won him several paintball matches, somehow managed to beat both of them to the door and held it open, smiling at Penny as she entered their apartment.

"So, what is there to do for fun around here?" Penny asked, surveying the room and noting the multiple grease-boards. Her initial impression of the two men was immediately challenged - there was a board right next to the refrigerator that, if she wasn't mistaken, had fragments of String Theory, a spoof of the Bourne-Oppenheimer approximation and some quantum mechanics scrawled on it.

She stifled a laugh at the joke on the board and Lee smirked at Leonard, who took a seat in the linen armchair and pulled the foil containers out of the paper sack, setting them out on the coffee table, trying to ignore the fact that Penny had obviously understood the joke on Lee's board, while ignoring the equally complex (in his own opinion) humor on his own grease-board behind the couch.

"Are you both physicists?" Penny asked, sitting herself in the centre of the couch as Lee cracked one of the containers, screwing up his nose and handing the Lamb Kahari over to Leonard, reaching for what he hoped would be his preferred Saag Paneer or Chicken Vindaloo.

"Yeah, I'm in experimental physics at Cal Tech." Leonard put in, before Lee could even open his mouth. "I'm actually doing some really interesting work at the moment, you should come by sometime and see the lab."

"Oh, I'd like that, and I'll certainly see if I can make time in my schedule to visit the physics department."

"You said you were getting your PhD, what field?" Lee asked, grinning as he found the Saag Paneer and tearing the lid off it, digging in with a gusto that made his lactose-intolerant roommate want to gag.

"Chemical engineering. I finished my undergraduate work at the University of Nebraska, but the PhD there wasn't as focused as I wanted, so I moved out here. Then, of course, six months shy of finishing my doctorate I found out that my boyfriend of three years has been cheating on me. So, while trying to finish my doctoral thesis, I was forced to move."

Penny said all this so matter-of-factly that it took both men, although their combined IQ was well north of 300, a few seconds to decipher the fact that the only reason Penny was living across the hall from them at all was because she'd just gotten out of a long-term relationship.

"Oh, man, that sucks." Leonard was first to make the connection, and Lee quickly agreed with him.

"It's not so bad, really." Penny told them, leaning back on the couch. "I mean, now I have my own space, and time to work on my thesis without constant interruptions. I'll still have to go to work, obviously, although I may need to find another job somewhere closer than Burbank."

"What's your current job?" Lee asked, pausing in his appreciation of his cheesy-spinach lunch, thinking of the fact that his manager had been moaning about a lack of decent waitstaff lately.

"I'm a waitress at the Olive Garden, on North Victory Place?"

"Yeah, I know that one. How long have yo been waiting tables?"

"Since I moved to California, it was the mot convenient job I could find that allowed me to continue my studies."

"So, three and a half years?"

"Yes, three years, eight months."

"Well, I'm a waiter and bartender at the Cheesecake Factory, down on West Colorado. I can put in a good word with my manager if you'd like a job closer to home."

"Really? Oh, Lee, that would be fantastic!"

"No trouble."

Penny thought for a moment, as she took a mouthful of the Chicken Vindaloo she'd selected for her lunch, and after she'd swallowed, voiced another question.

"Your main source of income is as a waiter and bartender?"

"Oh, no, I'm part of the theoretical physics department at Cal Tech. I just work at the Cheesecake Factory for my play money."

"Play money?"

"You know, movies, candy, comic books. Incidentals."

"You read comic books?"

"I started when I tore my Achilles tendon, I was off my feet for two months. Leonard loaned me some old X-Men editions and I got hooked."

"I suppose we all need our vices."

"What's your vice, Penny?" Leonard put in, beginning to feel as if he were being edged out of the conversation.

"Well, it used to be cable television, but given my current financial status I don't think I'll be able to afford to get it connected in my new place, much less get a decent Wi-fi connection. I may be reliant on the schools' internet for the next few months."

"You can always use our Wi-fi, I'm sure the signal will stretch across the hallway, it works on the second floor." Lee told her.

"How do you know it works on the second floor?" Leonard asked, his eyebrows drawn towards his hairline again.

"I did some troubleshooting for Mrs Vartebedian after one of her grandsons downloaded a virus onto her computer. Remember, she made us those oatmeal-raisin cookies?"

"Oh, right."

"You'd really allow me access to your Wi-fi?"

"Why not? It's not like you're going to hog the bandwith, are you?" Lee had almost finished his paneer at this stage, and was eyeing the second container of Chicken Vindaloo still sitting, unopened on the coffee table.

"I can assure you, I would do my best to keep my usage reasonable. I would reimburse you, of course-"

"Don't be silly, I pay for it with my tips. I'll give you the password before you go home."

"Well, thank-you." The three of them ate in silence for a few minutes, Leonard and Lee exchanging the odd glance over their new neighbor's blonde head. Lee had just opened his mouth to speak when Penny put down the tinfoil container she'd been eating from, looked at her watch and turned to face Leonard.

"If you don't mind, I'd like to take you up on the offer of the use of your shower."

"Sure, it's straight down the hall."

"Thanks, you guys are really sweet."

She stood up and stepped past Leonard, disappearing into the bathroom. Lee spoke the moment the door was closed.

"Well, this certainly is an interesting development." He got to his feet and went to the refrigerator, pulling out two bottles of orange soda and popping both tops.

"How so?"

"It's been a while since a woman's taken her clothes off in our apartment."

"Hey, I know I'm in a dry spell-"

"How long?" He handed Leonard one of the bottles, an eyebrow raised.

"Oh, come on, it hasn't been that long!"

"Leonard, I live with you, and I have an eidetic memory. You're coming up on eight months."

"So?"

"So, the woman in our shower is not going to have sex with you."

"What? I'm not trying to have sex with her."

"Good, that means you won't be disappointed."

"Hang on, what makes you think she wouldn't have sex with me? I'm a reasonably attractive male specimen and she's certainly an attractive female."

"Leonard, you're not the same species."

"Oh, come on, you know I'm just trying to be a good neighbor."

"Yeah, right."

"That's not to say that if she were open to a carnal relationship, I wouldn't participate."

"However briefly." Lee finished for him, earning a glower from his roommate as he leaned against the pillar next to the end of the hallway, gazing down towards the bathroom door.

"Yeah, well, how badly is the Luke Skywalker shampoo going to affect your chances?"

"It's Darth Vader shampoo, Luke Skywalker's the conditioner."

There was a knock at the door and Leonard went to open it.

"Wait 'til you see this."

"It's fantastic, unbelievable."

Howard Wolowitz and Rajesh Koothrappalli came into the apartment, Howard brandishing a DVD and Raj flicking his dark hair out of his face, grinning at Lee who rolled his eyes.

"See what?"

"It's a Stephen Hawking lecture from MIT in 1974."

"Oh, come on, this isn't a good time." Leonard protested, but Raj was already in the kitchen, perusing drink options and Howard had loaded the disc into the DVD player before he had even voiced his objection.

"C'mon, it's *before he became the creepy computer voice*." Howard told him, flicking his lips with his finger as he spoke, emulating the infamous physicist.

"Yeah, that's great. You guys have to leave. Now."

"What? Why?" Raj asked, pulling out a bottle of water.

"It's just not a good time." Leonard muttered, determined to get his hound-dog friends out of the apartment before Penny emerged from the shower. Raj and Howard were great, once people got to know them, but they both had a tendency to treat women as somewhat disposable, and Leonard didn't want Penny's initial impression of his friends to be that of a pair of jerks.

"Leonard has a lady over." Lee told them, practically dripping sarcasm. "Not that he has a chance with her, because she's totally into me."

"What?" Howard demanded, almost dropping the DVD remote. "You're on the verge of breaking your dry spell?"

"No, she's just a new neighbor."

"Hang on, there's actually a woman here? In the daytime?"

"Yes, Howard. In the daytime."

"And you're anticipating..."

"I'm not anticipating anything-"

"So she's available?"

"She's not available, Wolowitz, she just got out of a long-term relationship and she certainly doesn't need your brand of cologne rubbed all over her." Lee put in from his spot on the couch.

"Yours either." Lee told Raj, forestalling him even as he opened his mouth.

Just then, the bathroom door opened and Penny stepped into the hall, wrapped in Lee dark grey cotton bathrobe. The tallest man in the room bit back a grin as Leonard frowned, and Penny came to an abrupt halt at the end of the hall when she saw that the number of men in the apartment had doubled in her absence.

"Guys, how do you get it to switch from tub to shower- oh. Hello."

"Hello there."

"Enchante, mademoiselle. Howard Wolowitz, Cal Tech department of Applied Physics. You may be familiar with some of my work, it's currently orbiting Jupiter's largest moon, taking high-resolution digital photographs?"

Howard stepped over to her and didn't seem to notice as she shrank back, clutching Lee's robe tighter about herself as he leaned against the wall, tilting his head at her.

Lee noticed her discomfort, and got to his feet.

"Come on, I'll show you the trick with the shower." He stepped past Wolowitz, delivering him a surreptitious kick to the ankle as he did, but that didn't stop Howard calling out as Penny followed him down the hall.

"Bonne douche!"

"Merci, monseiur." she shot back over her shoulder, and Howard staggered back, slightly.

"She speaks French?"

"Apparently." Leonard resumed his seat in the armchair and Raj settled back on the stool next to the kitchen island, biding his time.

In the bathroom, Lee pulled back their periodic table shower curtain (a gift from his sister when she'd found out that he was taking 'science-y' classes at college) and spun the water to hot, before using both hands to jiggle the knob on the top of the faucet until it disengaged, sending the water through the other pipe and out through the shower head.

"It gets jammed sometimes, I think I've used about three cans of WD-40 and it still sticks."

"Okay, thanks."

Penny stepped into the shower and drew the curtain, shrugging out of his robe and tossing it up to hang over the curtain rod.

"Oh, okay, you're just going to jump right in there..." Lee muttered, mostly to himself. He was about 95% sure that Penny wouldn't be able to hear him over the water.

"Is this yours?" she asked, sticking a hand around the curtain and tugging at the collar of the robe.

"Yeah."

"You don't mind me wearing it? I can wash it, if you'd like, although I'm not sure what the machines are like in this building..."

"It's fine. There's Herbal Essences behind Darth Vader, my sister left them here last time she visited." He pulled his robe off the curtain rod and hung it up next to the door, then took a fluffy red towel from beneath the sink and tossed it up in its' place.

"Oh, thanks. Who does Darth Vader belong to?"

"Leonard. I'll leave you to it, then." He stepped over towards the door, but stopped when Penny spoke again.

"Huh. Oh, Lee?"

"Yes?"

"Thank-you for this."

"Not a problem. If you need anything else, let me know."

"Well... do either of you have a truck?"

"Yeah, I've got a Ranger. Why?"

"Well, there are a few things still at Kurt's place that I couldn't fit in the Volkswagen."

"What things?"

"Well, my sofa and a TV. I can come with you and help get around Kurt-"

"Oh, come on, Penny. I know how it is with breakups. Give me the address, I'll get Leonard to come with me and we'll go pick them up for you this afternoon."

"I suppose..."

"I insist. And I'll threaten Howard and Raj with grievous bodily harm if they try anything untoward."

"You really are a genuine southern gentleman, aren't you, Lee?"

"Born and raised in East Texas, Miss-soon-to-be-Doctor Olson. It's in my blood."

"Thank-you, Lee."

"You're welcome."

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"Why the hell did you agree to this, Lee?" Leonard demanded, sitting in the passenger seat of the Ranger and glaring at his roommate.

"Because you wanted to be good neighbors."

"Yeah, but I didn't imagine that would involve leaving her alone in our apartment with Howard and Raj. Those two are so pushy she'll probably never speak to us again after leaving her alone with them all afternoon."

"Oh, come on, this will only take an hour."

"Lee, we have no idea who we'll be dealing with."

"His name is Kurt and he works at a gym. How bad can it be?"

Pretty bad, it eventuated.

Kurt decided immediately upon hearing Lee's voice through the speaker that he was Penny's new boyfriend, and was therefore to be summarily ignored.

After Leonard and Lee followed a pair of Girl Scouts through the glass doors and made it up to Kurt's apartment, Penny's ex-boyfriend was revealed to be three inches taller than Lee, and a good thirty pounds more muscular.

"Look, Kurt, we're not here to fight you. Penny just moved in across the hall from us and asked us to bring my truck and pick up her sofa and TV."

"That TV is mine, and I tossed the sofa in the Dumpster this morning. Get lost."

"Come on, man, you didn't seriously put her sofa in the trash?" Leonard asked, incredulous.

"She walked out, so I tossed her stuff."

"Come on Leonard, this guy's a jerk. Not worth our time." Lee commented, turning his back on Kurt and began to leave.

"Who are you calling a jerk, stretch?"

Lee ignored him, continuing to turn away, until Kurt stepped forward and caught him by the shoulder.

"Hey, I asked you a question!"

Lee pulled away and before Leonard could react Kurt had drawn his fist back and slammed it straight into Lee's nose.

"Ah! Hey! What the hell?"

"Dude! Not cool!"

"That's what you get for calling me a jerk, jackass!" Kurt stepped back into the apartment and slammed the door shut in Leonard's face.

Lee's hands were on his face, trying to stop the blood gushing out of his nose from getting onto his shirt, and after a few fruitless pounds on the apartment door, Leonard caught his elbow and led him back towards the elevator.

"You've got a first-aid kit in the truck, right?"
"Mom insisted."
"Good. Come on, Penny will be okay without a TV for a couple of days."

"What about her couch?"
"She can sit on ours until we find her another one on Craigslist, people are always giving away furniture on there. Come on, let's get you home."

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"Oh my god, what happened?" Penny leapt up from the couch, where she had been sandwiched between Raj showing her digital photos of the planetary body he'd discovered earlier in the year on Leonard's laptop, and Howard hitting on her in six different languages, which she rebuffed with as much tact as she could muster, unsure if he was joking or not.

"Well, we met your ex-boyfriend."

"Lee, are you okay?" She skipped across the room and laid a gentle hand on his shoulder, peering into his face and wincing when she saw the purple bruise emerging on the bridge of his nose.

"Yeah, my sister used to do worse to me back in kindergarten. At least I'll have a good story to go with the shiners, this time."

"This time?" Penny latched onto his deflection.

"Last time it was because he thwacked himself in the face with a loofah mitt on an elastic string."

"And I got soap in my eyes, which didn't help. Sorry we couldn't get your TV, or the sofa."
"Oh, don't worry about that, as long as you're both okay. Tell you what, how about I buy you dinner tonight?"

"Oh, that sounds great. I know this fantastic little sushi place that does karaoke." Howard put in.

"Sushi and karaoke, sound like a good treatment for black eyes, Lee?"
"It'll have to do."

Raj spoke up. "I'll drive, the Camaro seats five."