Audiosurf
Audiosurf is a hella addiction for me already. Maybe it's just a craze, I dunno, but each time I'm playing I reach that "one last round" stage, or more appropriately "one last song".
Mash together Klax, Guitar Hero and Enduro: You would come up with something like Audiosurf. The big feature claim to fame is using your own music collection as the tapestry for the track.
I'd love it if a few of my friends could get as hooked on this as I am. It's a good excuse to see what everyone is listening to. Plus a little friendly competition is better for me than the aggressive masses (and the occasional cheats amongst them, relabelling songs is an occasional problem on the scoreboards). For anyone trying to add me to their friend's list in-game on Audiosurf I'm known as Rogdor and Michelle is Michelle_Mayhem.
It's a good deal for 10 bucks on Steam.
David Bowie - Space Oddity:
ELO - Mr. Blue Sky:
I've embedded two videos from Youtube, the first shows the racing "mono" mode and the second one of the puzzle modes.
Most any mp3, ogg, wma, CD, etc. will work, although results may vary. Tunes with a good solid beat seem to work best.

