is on sale on Steam for like 2 bucks! If you don't know it's a game that you can play, like a cross between F-Zero and Rock Band, that takes your music library and uses the songs in the game as the levels. It's kinda hard to explain so just watch this video.
So yea, its kinda simple, but the levels are different depending what song you upload. I'm sure if you put some metal in there things would get crazy. But seriously, it's just 2 bucks, and what other game lets you play Hallowed Be Thy Name as a level?
You can buy it here: http://store.steampowered.com/app/12900/