I may be late to the party on this one, but i just found this game, and its a good time waster
http://www.audio-surf.com/basically, it takes whatever song you want from your library, turns it into F-zero meets tetris, and lets you "Play" it. Very simple, very fun, very addictive.
it also has a cool way of doing songs, fast techno songs turn into insanely fast races where you just try to build little tetrsis, slow songs are more intricate, and provide less scoring combo's, but if you can figure them out, there higher points overall.
It keeps worldwide, local, and friend scores by song (i'm leading in the USA for score on "live forever", to bad im 112th world wide, darn you england!)
also, theres diffrent ways to play depending on what "car" you pick. an ecample would be "pointman" which is a car with the ability to pick up and store one note, or the "pusher" which allows you to use your front end to shift notes left and right.
all in all, a good way to re-discover your music. demo's free, and lets you play any song you want, upgrading to the retail lets you use all 21 different "cars" for different game modes.
figured someone might get a kick out of it