Backyard water fun

With highs consistently around 105-110 we need to find ways to amuse ourselves without the hassle of always going out. We've had a few friends over just to play in the backyard. Little M is always so good willing to do what everyone else is doing. He even lets his big brother use him as a target for his water gun.
We are hoping the drought isn't bad enough that our backyard activity doesn't get prohibited. The ponds and small lakes are dried up.