When you say the words "sumo wrestling," the first thing most people think of is two portly fellows locked in a deadly embrace. Robo-sumo is a different spectacle. Two tiny bots spasmodically twitch for 6 seconds, and then somebody wins.
This footage was taken at the 2010 All Japan Robot Sumo Finals during the human-piloted final match. Granted, the robots have a ton of autonomous functions dictating how to best thwart their foes, so their pilots aren't fully in control. Should there be a Japanese remake of Real Steel, it will be 15 minutes long.
Also, here's the fully robotic finals. It's somewhat less frenetic than the piloted competition (but not by much).