If you like live music from bands such as the Grateful Dead, Phish, SCI, DMB, etc. There is a peer-2-peer software that is called Furthernet. This is entirely FREE and entirely LEGAL. The reason it's legal is because it only allows bands that allow live recordings of their shows. This really is only for the JamBands style of music, but occasionally you can find some cool shows that aren't in that genre...

http://www.furthurnet.com/