I made a sensor system out of 2 Wii Nunchucks, an Arduino and some external circuitry to switch between nunchuck sensor reading. At a deadline of one of our presentations, a plastic gear from our arm had chipped some of its teeth so we weren't able to give motion demos. I whipped up a program using Processing (processing.org) to communicate with the Arduino and move a 3D simulation of an arm based on the sensor outputs.
I thought I'd share a few screenshots of the program. I'll have both the Arduino code, and processing code up soon.
Processing is a great program for doing graphical manipulations. It can also compile code to execuatable files.