In Japan, there is held a robot football competition every year, where robots compete in 5 a side, 1 a side ,and other match configurations.
The robots entering are normally matched in type, and they must have interesting programming and sensors to work as a team, while detecting the ball and obviously emplying some game strategy.
The current competition are mostly based upon wheeled robots, as legs are still not quite quick enough or well developed enough for this. Though there are some excellent robots in the competition - dont expect any robot players of the skill of David Beckham or for them to take on Arsenal quite yet.
Is there an Manchester United Robocup team? Not yet - but as it gains momentum, maybe we will see all the many leagues, teams and divisions as well as the diversity of the world of football (thats soccer if you arent British).
Maybe there will be robocup baseball and other sports cups, and we will one day see a Robo Cup super bowl.