One of the things the Poetry Foundation has seen fit to do with its buckets of money is support UbuWeb, a long-running and incredibly comprehensive repository of avant-garde art weirdness. The latest UbuWeb podcast, produced by the foundation, features the Western Roundtable on Modern Art, a seven-hour fest featuring Frank Lloyd Wright, Darius Milhaud, Marcel Duchamp, and others (via the inimitable Coudal). If that's not enough you can listen to UbuWeb Radio (courtesy of the Center for Literary Computing at West Virginia University).
Perhaps more exciting: a recording of Chicago '82: A Dip in the Lake, a historic new music festival that was previously only available on cassette from Belgium. For the performance, John Cage created a score (not performed?) called A Dip in the Lake, using a Chicago street map and environmental sounds from various city intersections. You can see a copy of the score here; from 2001-2003, Robert Pleshar "realized" the work, which is also available on UbuWeb.