The Music Animation Machine is pretty neat - you can actually "see" the music as it's being played. From their FAQ:
Music moves, and can be understood just by listening. But a conventional musical score stands still, and can be understood only after years of training. The Music Animation Machine bridges this gap, with a score that moves -- and can be understood just by watching.You can read more by clicking here.
It looks like a DVD is available that contains the video embedded below, plus others, with music from Scarlatti, Byrd, Bach, Beethoven, Chopin, and others.