This game isn't out yet, due in February, but I played it during the beta weekend (last two days). It's AWESOME. It's like the Guitar Hero kinda thing but you just load up any song you like and build Tetris-like combos with blocks that are on a highway you're "surfing" down.
Get it when it comes out : D
Also, this might work for some people if you want to play it before it's out...
First, Audiosurf Beta installer:
http://www.megaupload.com/?d=YNX2AF13Next, Fiddler (use to get around Beta Expired message):
http://www.megaupload.com/?d=FKT34QGJFinally, audiosurfboard (use to get around login problem):
http://www.mediafire.com/?2jjjx4xdvd1Run Fiddler, follow directions in text, run surfboard, follow directions, run Audiosurf.