Gravball

Gravball is a game played by human children. The game is played using a levitating ball, and it is played on repulsor courts. The gravball is "skimmed" across the court, although the mechanics of the game have never been described.

It is an activity available on playgrounds. As a child on Eridanus II, John-117 was not allowed by the other kids to play it, because he always won.

Trivia

 * A table game named "Gravity Ball", played in bars such as Eddie's In The Rock in The Rubble, may be a smaller-scale variant of the game.
 * The technology used in this game serves as evidence that humanity had developed anti-gravity technology prior to the Human-Covenant War. It is also possible though, that this "anti-gravity" was just provided by superconducting magnets.