Glow sticks in the pool, great for night swimming! Not sure this would be the best idea for a big in ground pool (would probably take a couple hundred sticks), but would definitely be cool in a kid pool or an above ground pool!
13 Crazy Pool Accessories That Totally Redefine Cool
A pool game. Our kids make each color a different point. When it's their turn, they throw a noodle stick and when it goes through a circle.they score points depending on the color. Materials:noodles,duct tape, pvc pipe and rope.
If I ever have a pool I'm totally going to get these! The Ocean Art Light-up Jellies from Swim Ways are eerily life-sized jellyfish decorations for swimming pools. Each light-up jellyfish has LEDs inside and glow as they float across the pool.