Booty Symphony: Quite possibly the awesomest combo ever: T-Pain and butts. Kyle eloquently explains T-Pain's Nappy Boy's Booty Symphony :

It's not as crazy as it sounds! Just tap the various booties on the booty soundboard-including snippets from Nappy Boy songs like Tay Dizm's "Point Em Out" and Young Cash's "I'm a Freak"-to create a short, stimulating 30-second video. OK, maybe it's more crazy than it sounds.

Ah-mazing in an app. Free or $3.