Life-Size Katamari Lives!

This is pretty cool. If you've never played this game it usually uses the two analog sticks on your controller to drive the on-screen ball like a tank. This would be much easier...

Kellbot! � Life-Size Katamari Lives: "It uses an optical mouse to track the ball. I gathered up some cheap PS2 controllers, ripped out the potentiometers on the analog sticks, and replaced it with a digital potentiometer and an arduino. The arduino takes signals from two PS/2 mice (one for each analog stick) and adjusts the potentiometer accordingly."