Latex Color Balloons
Balloons! ALWAYS helium, never air. If you want all the time fun, get a small tank of helium and refill it from time to time (some florists do this). You will also need ribbon; otherwise what's the point? I always loved tying a few balloons together and seeing how much stuff I could get them to lift. I never managed to get myself airborne though. Kids can also use them in water fights - the possibilities are endless!