Hold a jousting tournament – on the water!
For a donation, teams can participate in the joust. You can also charge admission to watch the event. Canoes build up the best speed, but inflatable rafts can be used for a safer environment. Use a long padded pole for the lance, and try to knock the other person off of the middle section of their canoe while the rest of the team paddles. If that is too dangerous, then use a water gun or water-filled bucket. Helmets and life jackets required.