A/N: *gasp* This is not a Romione fic! Nope, it's Jily and it's my first time writing it, so I hope you'll excuse me. I'd also appreciate if you pretended that batteries do work at Hogwarts, it's for a good cause (I didn't want to wreck Lily's records). Based on a certain Tumblr post. Many thanks to ftlhasthetardis at Tumblr for beta-reading this! :D

Disclaimer: I don't own Harry Potter or ABBA.

Only Seventeen

'Care to explain what this is, Evans?'

Lily looked up from her N.E.W.T.-level homework to see James raising both eyebrows at her from where he sat on the floor next to her record player. Her headphones were draped around his neck, and he held up an album. James didn't call her Evans anymore unless he was teasing her, and Lily could only guess why he was doing it now.

'It's ABBA,' she said loftily, just in case he was. 'They're very popular, I'll have you know, and catchy too.'

'You don't say.' James was clearly suppressing a grin, his disapproving frown and pursed lips straining to stay in place. 'Catchy, yeah? The one about the dancing queen, though…'

'What?' Lily asked, aware of how defensive she sounded. 'It's a fun song! And let me remind you, Potter, that you danced like an idiot to the Bee Gees a couple of weeks ago… and sang when you thought no one was watching!'

'I was humming, not singing!' James sputtered. 'That was catchy, too!'

Lily laughed at his mortified face, and he threw a ball of discarded parchment at her head. She swiftly caught it and flung it back, hitting James on his upper arm.

'Oi!' James said, pretending to be hurt. 'You'd make a fine Chaser. Have I told you that?'

'Only about a million times over the past five years.'

'Yet you won't budge. This year is your last chance, you know.' Lily rolled her eyes. 'Anyway, you know who's turning seventeen after Christmas break and likes Muggle music, don't you?'

Lily thought about it for a moment, and then scowled at him. 'Yes. What are you planning to do, throw him a party and make him walk down the marble staircase to "Dancing Queen"?'

'Oh no, not the marble staircase. The one from the dormitories will do.'

Lily chortled in spite of herself at the mental image.

'Are you serious?'

'No. I'm James. That's the person I'm talking about, though,' he said brightly.

'Oh for goodness' sake. He's your best friend!'

'Yeah, I know! D'you reckon he'll let me have the first dance?'

'Don't be a prat.'

'You know he'll love it, Lils.'

Lily had to admit that he was right. Sirius Black was the last person who would get offended at a prank that consisted of him acting like the drama queen he not-so-secretly was.

'Will you please bring this with you to Hogwarts?' James pleaded, holding up the ABBA album again. 'We'll make it work on one of the gramophones. We'll play it when Sirius comes down to the Common Room on the morning of his birthday.'

'If you put this in a gramophone, it'll only earn you a well-aimed hex, since you'll destroy my record. But my record player works with batteries; it'll do.'

'Wicked!' James beamed. Lily shook her head but laughed as well.

'Are you done snooping around my things now? Come here and work on your homework, or I'll be done and bored before you even start.'

'Of course. I wouldn't dream of letting you get bored,' James replied, taking off Lily's headphones and bouncing to sit next to her on the desk. 'But after that, we've got a party to plan.'