Kingball is a sport in The Sims Medieval. It is unlocked by building the Kingball Court. It can be played by both NPCs and Hero Sims. When Sims play Kingball, they can gain positive and negative buffs. It resembles tennis but uses a much bigger ball, paddles rather than rackets, and can be played by up to three players. In a three-player game, the kingballers stand in a triangle and pass the ball to either of their two opponents to try and catch them off guard.
The Blacksmith can forge plates for the game.
Placing the Kingball Court in your kingdom increases its capacity for Well-Being by 1, Security by 1, and Culture by 2.