You could approach him, pull out your iphone (assuming you have one) and ask, 'Excuse me, do you know how I can repeat one song over and over again on this thing?' If he says No - he's not interested. If Yes, then he'll either be the hero and figure it out, or help you in the process (assuming again you already know how to do it). Also, it gives you a subject of conversation on the song you like. If he likes the song, then even more awesome, b/c you get to talk about music. Yeah, I've given this a lot of thought..