Really cool robot called "Rezero" has been created by 10 undergraduate students. It balances on a single ball -- though the ball needs to keep moving to stand up, it can move very dynamically with the single point of contact to the ground. The creators note that at present it's just an experiment but imagine it might be used as a "tour guide" in exhibitions or parks, or used in hospitals to carry around equipment. Looking forward to see if this gets adapted and used anywhere beyond this experiment.