[Marc S.]

I think its funny that so many people are actually taking the water theme literally. It's entirely possible that it could be a water game and yet have not a drop of water on the field.

2009 was a moon based game where robots drove over "Regolith", a very flat and slippery material(although actual Regolith is made up of loose dust, soil, and rock) on a field called "The Crater".

Maybe next years game uses "Water", a dry slippery material(similar to "Regolith"), on a field called "The Ocean".
While I'm at it, the game piece could be a sinking ship(Titanic's 100th Year anniversary), or several classic video game items(Atari's 40th and Nentindo's 20th anniversary). That's my first guess for the next season.