Keep punch from becoming diluted - Fill a balloon with water, freeze, then peel off the balloon. You now have an ice orb with little surface area to cool your punch. Less surface area means less melting!
Balloon ninjas to shoot with nerf guns. This is a fantastic idea! Great for little boys! I know this was posted as an idea for little boys. but I think I'd like to have a nerf gun battle with these ninjas.
Layers of the Ocean: Under the Sea Science Activities - Learn about ocean layers & zones with this creative science activity kids & teens will love! Fun way to discuss marine animals and how light travels thru water -- STEM for kids
Ice Balloon Lanterns: Fill balloons with water then freeze. When they're about frozen, snip the top of the balloon and peel away. Drain any excess water. It's important that one side of the balloon remains unfrozen/open, so you can place a candle inside.