From Ludocity
Designer: Adam Skory, Adam Nelson
Year: unknown
Players: 2
Stuff required: A hard-rubber medicine ball. A trampoline.
Crew required: None
Preparation: None
Time required: 15 to 20 minutes per game.
Place required: A grassy open space with at least 15 feet of clearance on all sides.
Activities: New sport
This is a playable game - it's finished, tested and ready to play.
This game is made available under an Attribution-Noncommercial Creative Commons licence. (What does this mean?)

Play your way to a better body.

History and Influences

Simmons was created by Adam Skory and and Adam Nelson as an adjunct to crossfit workouts. It is influenced by Monkeyball, Tchoukball, Hooverball, Tennis, and a love of physical danger.


A medicine ball weighing at least 10lbs/4.5kg and a mini-trampoline.

Playing Space

A clear grassy area with at least a 15ft/3m radius around the mini-trampoline. There are no "sides" in this game.

Number of Players

This is a two-player game. Doubles should be theoretically possible, but seems awfully dangerous.

Gameplay and Rules

Players take turns bouncing the medicine ball off of the trampoline, touching the medicine ball with only one hand at a time. Points are scored when one's opponent drops the ball, fails to catch it, misses the trampoline, or touches the ball with both hands at the same time. The game is won by having at least two points more than one's opponent, above an odd number of points decided in advance.

The game ends up being part weight-lifting, part basketball, and part tennis. The main challenge to the game is to quickly change the direction of the ball so the other player cannot anticipate where it will go. Unlike other ball games, however, the inertia of a medicine ball means that instead of moving the ball around your body, it's better to learn to move your body around the ball. Most points end up being scored when you can get your whole body behind the ball and quickly accelerate it onto and off of trampoline at angles the other player isn't expecting.


  1. Players may never touch the ball with both hands at the same time. Passing the ball back and forth between hands is allowed.
  2. No strict shot clock is enforced, but players should make a good effort to throw the ball quickly.
  3. Players volley for first serve,
  4. The ball is thrown directly onto the trampoline, and must bounce to at least knee-height.
  5. Each player then catches the ball and quickly bounces it back off the trampoline. Game play continues back and forth in this manner.
  6. If at any point a player throws the ball onto the inner rim of the trampoline, bounces it lower than knee-height, or bounces it at such an angle that it would land right back on the trampoline, the other player is given the option of stopping game play and taking the serve. No points are scored.
  7. If at any point a player drops the ball, fails to catch it, misses the trampoline, hits the outer rim of the trampoline, or touches the ball with both hands at the same time, game play stops and the opposing player is awarded one point and given the serve.
  8. A player wins by having a score past a minimum number of points decided in advance (usually an odd number between 5 and 15) and at least two points greater than the other player's score.


A 10+lb medicine ball traveling at 20+mph is really, really dangerous. When you first start playing, you will get bruised. Don't pay attention and you will get hurt far worse than that. By reading this website and playing this game, you agree to play at your own risk entirely and to not hold us responsible for telling you about this or any other dangerous games!