Courtesy of the Make blog, check out Nyle Steiner’s Electronic Composition, using a variety of audio circuits which use bits of heated zinc instead of transistors. Nyle has done a bunch of experimentation with zinc negative resistance oscillators on his Spark, Bang, Buzz website, all of which are awesome.
httpv://www.youtube.com/watch?v=Z44jlvpRHXc
Wow! Steiner is a master — he was the solo synthesizer player on the Apocalypse Now soundtrack, playing a trumpet-like synthesizer of his own design (the Electronic Valve Instrument.)