Oscar sent in this cool looking Arduino powered robot. Apparently it was built by a group of 16 year olds for a soccer competition. The translated site has a lot more information about the ArduSoccerBot.
ArduSoccerBot is a kind of teaching which aims to make a robot soccer (in the style of the RoboCup Junior) using a single USB controller Arduino Diecimila.
More about ArduSoccerBot: Arduino soccer robot