So here's the plan. I perfected this with my friends circa 1990 at a wave pool water pack with my best buds.
What we did was we brought a football to the top of the slide and set up an order of who went first,..next,...next...last.
The mission, simple: the last person starts with the ball and has to pass the ball the person in front. Then that person has to catch it and pass to the next guy.
For beginners, getting the ball to the first guy before he splashes into the water is considered success.
Pro level though is getting the ball to the front AND then all the way back to the last guy before he hits the water.
Being a kid was the best