Dr. McLurkin's bots are the size of a small flower pot. Each one wears an infrared LED and four IR sensors, one on each corner, telling each bot where its nearest neighbor is at. Individually, each bot only "knows" where it is in relation to its nearest colleague, but give six of those critters an algorithm to work within, and you'll see some complex, coordinated bot behavior.
The exhibit catered to kids without talking down to them. The minibots squeaked, honked, and whistled like tiny R2D2s, singing "Hi Ho, Hi Ho" and "The Hokey Pokey" during different tasks.