check out this awesome program
from wikipedia:
Audiosurf is an IGF Award winning[3] puzzle/rhythm hybrid game created by Invisible Handlebar.[4]
Its track-like stages visually mimic the music the player chooses,
while the player races across several lanes collecting colored blocks
that appear in sync with the music.
heres what it looks like. it starts getting intense at about 1:40
http://www.youtube.com/watch?v=g_25vShx9a4&feature=related
heres the audiosurf website:
http://www.audio-surf.com/