Pandora

Pandora - Find New Music, Listen to Custom Internet Radio Stations
how cool is this!?
You enter a band, or a song you like and hit play, the Music genome project looks at "everything from melody, harmony and rhythm, to instrumentation, orchestration, arrangement, lyrics, and of course the rich world of singing and vocal harmony"
it then plays you as a internet radio station a listing compiled of you favorite bands, and bands like them you may or may not have heard of.
you can even, mid track select options such as:

• 'great, play me more of this'
• 'eugh, dont play this too often'
• 'sick of this track, keep it off the air for a month'

its half way between sticking with the music you know and love, and exploring the stuff you dont.
A great backing track system to everything and anything!

[Quick edit jus to say i LOVE IT!]