UPDATE: the audio is off the air, unfortunately. Mos Def's performance of Rzewski's Coming Together, was really something. Here's a different recording of the piece.
In case you missed it, here's the Brooklyn Phil's Fall Preview Concert featuring music by Mos Def, Frederic Rzewski, Lev Zhurbin, David T. Little and Corey Dargel. It's only up for a few more days.