this one sounds even easier to make: bubble snakes = easy quick craft. Cut the bottom off water bottle. Put old sock over bottom and duct tape. Add food coloring for fun. Dip end in dish soap mixed with a little water
This post has a water themed Birthday party including this relay: The first kid starts with a full cup of water, then pours it over his head and the second kid catches it and repeats and they keep doing this to see who can fill up a jar the fastest.