This is under the category of "cool geeky stuff bordering on automation". Every year teams of engineers (like these) and other smart guys build robots that compete in the Robogames. There's different events like soccer, running races, sumo(?) and art. But by far the most popular is the combat bots going at each other to the death.

There's a lot of videos out there but I think the best one is on Geek Entertainment TV. The Discovery channel did well on it's segment. Oh and this one is good too.