Audiosurf is nominated in three categories for this year's Independent Game Festival Awards; grand prize, audio, and technology. It's an interesting combination of a music visualizer and a match-three game, with elements of a racer.
When you start a game, you're asked to select a piece of music, with the application defaulting to your "My Music" folder (but navigable anywhere, including to, say, a CD in the drive). Once selected, it builds a race track from your music track; I'm not clear on the algorithm involved, but "intensity" corresponds to slope. The point here is that the same piece of music creates the same track, so that if you select, say, "It's Better at the Matinee," the track you're presented with will be identical to the track generated by someone else who selects the same song on his own machine.