Last summer, we had a water party for my 8 yr. old son. I stamped the invitations on blue paper with a water theme. The kids came dressed in their swimsuits. We gave each one a water gun, that I had bought at the dollar store. (this was also their take-home present). My older son was there with the garden hose for refills. After that we had water balloon games. We ate blue cake on blue plates, and drank blue Kool-Aid. Then, the kids played with the water guns some more, and finally my older son chased them with the hose. Everyone had a blast!