Go to a store and buy glow in the dark sticks (make sure you get two different colors). These are usually about a dollar or two a piece. Then go to a park or big backyard where you can run around. Use string to make a necklace out of the glow sticks.... In a group divide up into teams and have a glow in the dark water fight with squirt guns and water balloons. Just make sure the ladies aren't wearing white.