Ubu!

At long last, Ubu has returned after a long summer restructuring. Ubu is the finest place on the internet to download (mostly) legal music, movies, and documents pertaining to avant-garde, modern composition, spoken word, musique concrete, minimalism, etc. Their partnership with WFMU (the best free-form radio station... ever) has garnered an impressive collection of music from Glenn Branca, John Cage, Yoshi Wada, and Morton Feldman to movies featuring or written by Roland Kirk and John Cage (which I recommend), Samuel Beckett, and Guy Debord.

Some suggested downloads:
+ Glenn Gould: Radio Broadcasts
+ Yoshi Wada
+ Group Ongaku
+ John Cage Meets Sun Ra
+ The Tape-beatles

You'll probably hear a segment of that Sun Ra download this Monday.