There's so much fun to be had with ballistics, robotics, engineering and science in general. Way too much to fit it all in, especially considering we can only meet once every two weeks. But here are some potential long-term projects.
Potato Gun: Build One
Build a new potato gun. More powerful, more adaptable, smaller, bigger, easier to use, whatever -- just better in general. We could stick with combustion or move to a pnuematics-based system.
Potato Gun: Stress Testing
Fire a potato at things and see how well they hold up. Brick wall? Wood wall? Pile of cans? Pile of trash cans? A dummy?
Oh, wouldn't it be fun to have a dummy...
Potato Rocket [& Launcher]
Stick a rocket engine in a potato and see what happens. Or adapt the potato gun to work as a sort of potato rocket launcher. :)
Experiment with building rockets in different ways. Two stage, multiple simultaneous engines, booster rockets - you name it. Maybe have a contest, "who can build the coolest rocket."
Stick a rocket on the side of a miniaturemerry-go-round and make a rocket-powered merry-go-round.
Rocket-Powered Other Stuff
Name something, and we'll make it rocket-powered. Frisbee, for instance.
Well, not anything... safety first, remember! :)
Build a bridge. The one that can support the most weight wins!
(Bonus points for making it potato gun-proof.)
Remote Controlled Car/Boat/Plane
Bonus points for making it intelligent, and thus a robot. More bonus points for making it rocket-powered! :)
Make a soccer-playing robot... or, even better, a team of soccer-playing robots!
Make other cool robots. :)
Bigger? Smaller? Faster? Maneuverable?
Calculate how far a potato or rocket goes, project trajectories, and so on. This would just be incorporated into our other projects.
I will update this list as we come up with more ideas. Stay tuned!