Balloon Shot Put: Heave a balloon, just like a shot-putter. Place a few dried peas inside the balloon before you inflate it. Between the wind and the peas, everyone should have a fair chance.
Hula hoop discus: Fling that hoop and see how far it can fly. Little ones can roll it, if they prefer.
Water balloon archery: Use a toy slingshot or a big rubber band to launch water balloons at a target.
Swimming gear relay: The first person runs to a plastic tub and puts on all the gear (swim cap, goggles, flippers, blow-up ring, etc.), then waddles to a teammate and hands off the gear.
Paper skate race: Each person is given two pieces of construction paper. Lay one piece down, step on it, put the next down, and step on that until you reach the goal.
Foam basketball toss: Take a pool basketball set and give everybody five foam balls to throw. Move the basket closer for the smallest players.