Had a similar type of thing going on at my town's pool growing up. We never really had teams, just a couple of guys on each side of the pool, we would mainly have contests to see who could make the nerf ball land in the gutter the most.
What was really fun was getting a football game going, where the gutters would be the goal line.
Edit, just read Steve Dave's further explanation of Gutter Ball. Yeah, that's awful, sorry man. What's fun about being at the pool and playing a game but not being in the water?