[pauluffel]

I like your reasons for guessing that drums will be important, but I think it would be much more interesting to use musical drums than simply drums as containers. Using audio to help with autonomous would be fiarly economical and would add a huge new aspect to the game, though making the audible data useful without having too much interference would be rather difficult (imagine the huge numbers of fans screaming in the final match of Championships...)
Possibly using ultrasonic sensors to measure distance or having some sort of "drums" on the field that would produce ultrasonic or subsonic beats that you could only find and hunt down with sensors on your robot? Sounds fun and challenging to me.

Also about the game but not related to drums, I'm hoping they make the field more dynamic, with a large random element, like squirrels or small dogs or some other sort of animal, though PETA (the humane treatment of animals nuts, not the People for Eating Tasty Animals) would mug Dean if live animals were part of the game.