I've never been to one of these things, I'm only a two-hour drive away, and perhaps I should go...
Related to this, last Saturday I attended the regular monthly meeting of the
Atlanta Hobby Robot Club where (among other activities) Dale Heatherington showed of his latest contraption he'll take to Dragoncon this year, the "Scary-Go-Round 30 pound Combat Bot (June 2007)" linked to at the top of the page here:
http://www.wa4dsy.net/robot/
I saw this thing spinning on the floor at about three revolutions per second, and yes, he was able to steer it.
Dale has build successful battle bots in the past. He's seen in this video, especially about 3 minutes into it pulling a rubber snake out of his bot:
http://video.google.com/videoplay?docid=4661556651241739290&hl=en
Building robots is yet another thing on a really long list of things I want to do...