Bottle caps(Potentially relevant link)
Long, long ago my brother and I started collecting bottle caps. Eventually, he stopped (and gave me some of his), but I've never gotten over it. At this point, I kind of wish someone would give me a few bucks and take them away, or take them for free, or something. I'm sure there's an art student at ECU who'd like them. Maybe I should post a flier.
Nowadays. the collection grows primarily thanks to my dad drinking gallons of Diet Dr. Peppet, but during the Pepsi+iTunes promotion this year, I went through recycle bins and trashcans at ECU daily, and all in all managed top win over 100 free songs without drinking a single bottle of soda. Which isn't to say they were all winners.