I worked on the 932, Current Designs's flagship interface, for over three years. I utilized all the capabilities of the embedded microcontrollers (two PIC18F4550s), which interfaced with a variety of ICs and communicated over USB, serial, parallel, and optical connections. The 932 enumerated as a composite USB device, appearing as a HID keyboard, mouse, and joystick simultaneously. I wrote the firmware (including the USB stack) in pure assembly to save memory and maximize execution speed.
This is the software interface to the 932. It is written in Python but distributed as a binary on Windows and OS X. Users can use this program to upgrade firmware, change light levels, change button output, change modes, and read documentation.