There were also a bunch of teams there from a robot competion. My son spent a lot of time driving some of the big 'bots around. He didn't get into the some of the smaller ones scooting around, but he really liked the big stuff.
My favorite was the juggler. She had a cigar box fanny pack on that contained four motors and a spark generator. The motor shafts had zip ties on them so when they spun they'd make a rythmic clicking. The circuits where all incomplete, with wires led up to bare conductors in gloves or rings she was wearing. While juggling, when she caught a conductive ball the circuits would be complete causing the motors to spin or the spark to spark. This resulted in her juggling being accompanied by her own cool little rythm section.