This cute little robot uses a 3-axis Freescale accelerometer to balance. This board is mounted underneath the Chumby and the Chumby actually runs it. This Chumby is running a Linux port of RobotSee from EMGRobotics.
All in all, I have to say that this pretty amazing to see. If you’re not interested in the technical details, you can jump to 1:40 to see the Chumby robot do its thing.