That's some serious balancing. Engineers at Boston Dynamics are making progress with "Atlas", the 180cm, 150kg humanoid robot. Still a long way to go from this to fast robot ninjas, but it's already intimidating as it tries to do the famous "Crane Kick" (or at least the stance) from Karate Kid.
You should turn the volume down a bit for this one, there's some serious noise coming from the poor robot. So much for sneaking up on enemies and doing that kick.
Atlas KarateKid [DRCihmcRobotics, YouTube]