At one point I was in a experimental trio with musicians Cynthia Payne and Leaf Tine. We would get together and play experimental music over Internet 2 with Stanford CCRMA and Rensselaer. Leaf's primary instruments were a circuit bent keyboard, amplified rocks, and a joystick synthesizer, which I was always envious of.
Since I am now acquainted with electronics, I created my own joystick synthesizer. It is a modified pc joystick with a built-in square wave oscillator and lowpass filter. It is an excellent sound source to use on its own or feed into effects. I have posted the schematic and parts list so that you can build your own (I take no responsibility for damage you cause to your speaker or yourself ... etc)!
Sound exploration with Joy Stick routed through effects: http://richard-c.com/touch/joystick/JOYSTICK-DEMO.mp3