This past weekend, Tokyo's 12th Robo-One Grand Championship featured 25 two-legged robots trying to punch and jab their way to victory. One of them even sang a Christmas carol, only to get knocked over by a punch form a penguin-headed robot. The winning warrior, which earns the title of world's strongest two-legged fighting robot, has to throw and dodge punches and pull Rocky-Balboa-like feats of getting back on its legs after a devastating blow. No lasers or missiles allowed.—Gregory Mone
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.