If folks aren’t aware, you can go to Archive.org and stream or download tens of thousands of shows by artists. There are currently 2,774 Grateful Dead shows, stretching back to 1965, but those are coming down at some point — at least the soundboards are — as the Dead will be releasing the entire archive via iTunes at some point in the not-so-distant future.

http://www.archive.org/audio/etreelisting-browse.php