When we were young sprinklers were for watering the lawn and running through them in the heat of summer was just a bonus. These days sprinklers are bonafide outdoor toys and if you're lucky enough to have a yard you probably have one. What's great about the Ultimate Beach Ball Sprinkler is that it's not intimidating even to very young children. It doesn't whiz around and you don't have to time your approach to it with the stealth of a Navy Seal.
It can be rolled around the yard or weighted down with water to remain in one spot. Four separate sprayers give every kid (and parent) a chance to cool off.
Here is one source for the Ultimate Beach Ball Sprinkler.