Alright, general introduction: there is not going to be any cohesive tone or era here. It all depends on the song. I have allowed myself to skip songs that gave me no inspiration whatsoever. Sometimes lines are lifted straight from the song, sometimes I've just drawn on the theme, or even the feel of a particular line that stuck with me. The time period will vary, from MWPP right up until OotP. So will the length; a few of these are just a couple of lines long, while others - like the first chapter - are a fair bit longer. In the beginning I'll be posting the ones I'm finished with something like once a day, and after that I'll just update whenever I write one!
I'm not sure how I feel about this first one. It's a bit of a tricky subject to start off with, but... it's what shuffle assigned me! The song is Olyckssyster by Lisa Ekdahl. You can probably find a translation on Google if you feel like it, but I think the theme should be fairly evident.

Sirius was breathing heavily when he finally reached the common room, near shouted the password at a very insulted Fat Lady and scrambled through the hole. He let out a strangled cry as he spotted James, playing chess with Lily; the bespectacled boy raised his eyebrows in alarm.
"Prongs," Sirius managed. "Prongs! Prongs, have you seen Moony? Was he- did he come by here?" Lily, with her copper hair in an elegant braid, had half-turned in her seat to stare at Sirius in bewilderment. Her boyfriend shrugged helplessly.
"Well, yeah, I guess, he-"
"Where was he going?" Sirius had rushed over to his friend's side. "Did he tell you? Was he upset?"
"I'm not sure, he might've- Sirius, what's going on?"
"I think he's in the owlery," Lily offered, concern clear on her face. "He had a letter. I didn't see what it was."
Sirius immediately spun around, planted a kiss on the mouth of the shocked redhead and rushed back out, ignoring James' outraged cries. He took the stairs two at a time, pushing past a few horrified firsties. His heart hammered in his throat; he forced himself to focus. Find Remus. When the doorway to the owlery came into view, he stopped only for a second to catch his breath, before sliding the door open calmly in a tremendous effort of will. There was somebody sitting on the far side of the room, black school robes flowing onto the floor around them as they hunched over; Sirius knew without having to look that it was Remus. He approached his shuddering form carefully. The boy, who he could now see was crying silently, gripped the wall with his long, slender fingers, rough with scars. His wand had been carelessly discarded, and it lay beside him, emitting a soft light. The owls were watching the sobbing boy with their heads cocked curiously. Sirius reached out to lay a hand on his friend's shoulder; Remus started, turning his head slightly. His eyes were red-rimmed and glistening.
"Pads," he whispered, voice hoarse and strained, before wiping his wet cheeks on the sleeve of his robe. He pulled his knees up against his chest and continued to face the wall. "What do you want?" Sirius' mouth was a thin line as he kneeled beside him, wrapping his arm around his shoulders.
"Remus, listen to me. You need to tell me what's wrong. I can't help you if you don't talk to me." Remus' head sank into his crossed arms.
"You know bloody well what's wrong," he muttered. "Don't act like you don't. You're a terrible liar."
"Alright," Sirius conceded. "The wolf. This is about the wolf."
"Of course it's about the wolf!" Remus' voice had risen into an angry snarl. "Can't you see I'm-" His voice broke, and Sirius moved closer.
"Moony," he said, very quietly. "Why did you come up here?" He was met with stubborn silence.
"Please," he pleaded. "Were you-" He swallowed uneasily. "Were you going to… hurt yourself?" There was another long period of silence before Remus responded.
"Figured I'd have a go at flying." His voice was barely audible. "I've not got a broom, but I'm sure I'd…" He trailed off. Sirius drew him into a tight embrace, wrapping his long arms around him from behind; Remus did not relax, but leant into him and sighed.
"Moony, I love you." More silence. "I do, you know that. You have to promise me never to do something like this again. Please."
Remus closed his eyes. "You say that like I have a choice."
Sirius pressed a kiss to his tear-streaked cheek. "Of course you do. You always do. You can't control everything, I know that, but you can control this. You're the strongest person I know, Moony. You really are. Please stay with me." With this, he got up; he offered Remus his arm and, when he took it, drew him onto his feet. He wiped the last of the tears from the other boy's face with his thumb, smiling.
"Let's go to the common room," he suggested. "I think we're annoying the owls."