Sorry for joining the party so late. My thoughts:
Water Game: Ain't gonna happen. How many regional venues have pools?How many schools have pools that they'd be willing to devote to robotics? What kind of clean-up is required when various lubricants spill / leak, or when bits and pieces fall off?
Shooting Game: Agreed, we've thrown a lot of things in recent years, time for a break. (Unless, as some suggested, we tie this in with the Olympics, and have a biathalon game -- with REAL shooting!
)
Stacking Game: My personal favorite, although it should be noted that Stack Attack in 2003 came so dreadfully close to BattleBots that the GDC is probably hesitant to repeat this. Stacking (or even "building"?) could be very cool, though.
Dodge Ball / Laser Tag: Potentially interesting, but A) how do you detect hits? Wouldn't this be a bit boring to watch?
Poker: VERY cool from the building / programming standpoint. But again, boring to watch?
Okay, let's combine ideas: Robots have to build a house of cards?
