You can build your own Theremin!!!
Theremin Building
A way to play thousands (literally!) of games on your Atari 2600!
(Also a link to the Classic Video Game Syndicate!)
HappyCart
A MIDI Interface for the Palm Pilot, with rudimentary software!
It costs only $30....get yours!!!!
PilotMIDI
The EZ-Kit Lite is a BOON to electronic music experimenters. It's very
inexpensive, and you can
use it to make any effects you can program, synthesizers, and whatever else.
The sound quality is very good. And support is growing for it. See what
the EZ-Kit Lite hackers are doing:
EZ-Kit Lite
This french dude wrote this software...It's basically a version of
Rebirth for Linux. I haven't checked it out yet, but you can become
an alpha tester now, and check it out.
Groovit