These three are from SilverHeart09's story '50 Things Tony Stark Is Not Allowed To Do'

20-Jump out the window in his armour and give Pepper a heart attack
Pepper sighed as she approached Tony's office. She wasn't sure how much more of this she could take!
She knocked on on the door softly, but found it was slightly open. Confused, she pushed it open more.
The office was empty. There was no coat on the hook, no laptop on the desk.
"Tony?" She said nervously. Wasn't one of those on the list to make her jump with hot coffee in her hand? She'd lost count of where he was now. Hoping to avoid a scold, she put down the coffe she held, next to Tony's mug. It was sitting on the desk, half full and cold. So he had been in then. "Tony? Are you here?" She asked a little louder.
Then she heard it. The massive crash that came from above. It made her practically jump out of her skin, close to screaming. Broken glass fell outside the window like diamond snow.
Terrified, Pepper went over to the window. On the ground, people were scattering, looking up in amazement. She swallowed, her heart pounding against her chest, and looked up. Tony was falling, in his suit, at breakneck speed. He didn't even have a helmet on. As he passed Pepper's floor, she heard him yelling, 'woooohooooo!'
The shock of it sent her backwards, and she fell onto her bum, eyes wide in terror. What did that crazy fool think he was playing at?
He must have spotted her, because he stopped his descent and flew back up too her window. He grinned at her then breathed on the glass. He wrote a backwards '20' into the condensation, winked at Pepper, then fell backwards again.

21-Hack into Rhodey's account and change the profile picture, username and start-up noise
After her ordeal, Pepper went back to her desk, hands shaking.
When Tony finally arrived, thankfully, he left Pepper be. She still glared at him, letting him know that when the shock was gone, he should panic. He just strolled past her, cocky and whistling to himself.
Pepper thanked the-powers-that-be for a peaceful morning. It was almost as if Tony was avoiding her, he probably knew what she wanted to do to him right now. Even if that was the case, Pepper managed to get workers in to repair the window before 10am and actually got some good work done. She was just getting ready to leave for lunch when Rhodey came storming in.
The colonel was red-faced, carrying his laptop which was loudly blurting "Fever"
my one and own i wanna get you alone, give you a fever! fever! Yeah!...
Pepper actually giggled despite herself.
Rhodey hit Tony's door. After a small pause, it opened.
"Yes?" Tony asked innocently. "Oh, will you turn that down?!"
Rhodey ground his teeth. "It won't, Tony. You should know that. Now fix whatever the hell you did to it!!"
"Moi?" Tony said, touching his chest, just on the Reaktor. "What would i do to that?"
It was all an act. If Pepper hadn't have been there, Tony wouldn't try to act so sincere, Pepper was sure of it. "Tony..." She said his name fact, it was almost a growl. She was determined he wouldn't mess up the rest of her day.
Wincing, Tony grabbed Rhodey's lapyop and pulled him into his office. Pepper sighed and left for lunch.

22-Ditto Pepper's account
Pepper returned munching on a little guilty pleasure. Chocolate was one of her weaknesses.
Content once again, she sat at her desk and started up her computer. She entered her password and waited patiently, eating her chocolate, for it to start up. Then she nearly choked.
A very, very loud version of the 'Birdie Song' Filled the room, coming from her laptop.
She frantically searched for a way to turn it down, or better, off. No such luck.
Pepper wanted to pull her hair out. The Stark Industries Internal Messanger popped up on her screen.
CHANGES ACCEPTED
UPDATES LOADING...
Updates? What changes?
Her username had been changed to 'TonyStarksFantasy'. Pepper gasped in horror.
She bit her lip. If Tony was being that cheeky, what would the damn picture be? A picture of Tony himself, complete with tons and tons of little hearts around his face. Pepper picked up her laptop and stormed into Tony's office.
"TONY!"
He physically flinched. "Yes dear?" He grinned at her again. She put her laptop on his desk, faceing him. "Aww Pep thats sweet. I never knew you felt that way."
Pepper ground her teech in anger. Tony's smile diasappeared.
"You want me to fix it?"
Pepper didn't even need to nod.