This is what happens when you get a couple of cheap RC cars and add proximity sensors, extra batteries, robot brains, and name them Steve McQueen and Burt Reynolds: totally-automated racing all around your house. These electric robocars can detect the walls around them and race against each other for as long as the batteries last. The resulting Tron-lightcycle-like action is impressive.
The cars use a CPU called Picaxe 28X, running the Picaxe operating system. The program that runs them have the objective to "stay close to the walls, drive fast, and overtake the other," using the sensor to avoid obstacles by turning, as well as manoeuvring around them using the reverse and 3-point turns.
I want them. Fortunately, Frits—the developer—says that he will release instructions soon. [Let's Make Robots]