This might be a craft do-able for the older kids! Make and decorate a spaceship/car from the water bottle, attach wheels (make those from the bottle caps?) and then attach a balloon to the top where they could blow it up and race the cars with each other (maybe in the dining hall for a flat surface!) The only problem I can see would be finding a way to attach the wheels so they would roll, but if we could do that, this would be a really fun craft!!