Here is a very cool example of what can be done with LEDs on robots.
http://www.youtube.com/watch?v=06c-6VXEHrg only pay attention to the first ten seconds XD in 2011, we had the first logo flash on our robot in, if i remember correctly, 40 LEDs. One shape at a time. It really fit the game, and it taught people a simple electronics at the same time. As for power, it was using power from the distributions board.