9 bucks on Steam, and it comes with the Orange Box soundtrack.

http://www.youtube.com/watch?v=1-z6YK92otg

Enjoy!

what is that? fzero?

Nope, you play that game to your songs. It creates "track" for any song shorter than 25 minutes or longer than 1, I think. There's also like... 14 classes to play as well. It's fun, and well worth the 9 bucks. You'll have to rip your m4p's in order to play them though.

looks kinda like a mix between fzero and phase. overall though, just not something i'm too pumped about after watching about 3 vids.

I think it looks cool but really hard.