Before Play Begins--Set up your 4 bases for kick ball
From home base--have a sprinkler of some kind that the children run through to get to first base.
At second base--have a large bucket or cooler of water the children dunk their head into.
At third base--have a kiddie pool filled with water the kids much jump into and wait in until the next kick.
Between third base and home set up a slip and slide and have children slide to home.
Divide your children into two teams and play with normal kickball rules. If your children are upset because they do not get to do all the bases before they are tagged out; go with the "everyone gets to kick before the side is out" rule.