Vader is a LEGO sumo robot that I built when I got my first black NXT. It has three motors, two light sensors, and two ultrasonic sensors.
This year at Brickworld, it won the sumo event for the fourth year in a row. After being reprogrammed, it also won the joust event on Sunday.
It's won a few other events in the last five years, and has done much n better than I ever expected. At this point, I don't see taking it apart any time soon..