You pick up a bunch of swim noodles, or pool noodles, and throw them in the pool. The kids will use them to stay afloat and hit each other. But if you play with your kids, you can show them how versatile these things really are! For example, you can use them as light and portable construction materials for your backyard obstacle course:
Even for parents that are not very crafty or good with tools can make this simple but fun outdoor activity set. The only materials you need are about 40 swim noodles, 3 rolls of duct tape, some yard stakes (less than 20), and soccer balls.
Create a tunnel crawling course by pushing a yard stake into the ground, placing a swim noodle over it (through the hole in the center of the swim noodle), ending the swim noodle to form a semi-circle, then pushing another yard stake into the ground and placing the other end of the swim noodle over it. Make several of these and voila! Your tunnel crawl course is complete.
You can read instructions for several other components of your obstacle course, plus other handy uses for swim noodles at Housely.