Have an old floppy drive lying around that you have no use for, but can't bear to throw away? Software engineer and electronics hobbyist Michael Kohn created a circuit that will shake a floppy disk head at particular frequencies to make music.
Mike offers circuit schematics and the code needed to play MIDI files on the drive heads for free at the link below. If you're looking for an unusual electronics project with lots of geek cred here you go.
Floppy Music [Michael Kohn]