I first heard about contemporary composer Conlon Nancarrow when Zappa mentioned him in an interview. Nancarrow wrote music for player piano, sort of a pre-historic synclavier.
His "Studies For Player Piano" got released on four or five CDs some twenty years ago. Essential stuff.
If you've never heard his music, here's an opportunity to check out: his 1969 (!!) album:
-- link: Jan van Kemenade