Hi Ben,
I love the show. How about a USB midi contoller system based on a Teensy++? http://www.pjrc.com/teensy/
One could use a number of video game related input devices as inputs and you could have multiple people collaborate to make music together.
Here are some inputs that could all go into the same device:
DDR Dace Pad.
thumb sticks/analog joysticks
racing foot pedals
Wii ninchuck (accelleraomter and buttons and thumbstick)
giant digital buttons
touchpad (like from a laptop)
giant analog buttons
I have a teensy++ and a number of thease devices that I'm willing to make available. I also live in the Chicago land area and would be willing to donate my time.
Collin