Goat-Ball
This team game uses a furry, misshapen ball made out of stuffed goat-hide. The more lopsided and lumpy the ball, the better. Goat-ball requires a dozen to two dozen platforms (usually boulders, logs, and tree stumps) raised above the ground in a random pattern. Two teams of four clamber onto adjacent platforms, and a referee runs out to place the goat-ball on a platform somewhere roughly equidistant from the two teams. The teams then leap from platform to platform, each trying to be the first to reach the ball. Whichever team reaches the ball first is on offense.
When a team is on offense, it tries to complete three consecutive passes involving teammates on four different platforms (in other words, you can’t just pass it back and forth three times; you have to leap from platform to platform). If the team on offense completes three passes, whoever has the ball can try to hit an opponent with the thrown ball.
The team on defense tries to intercept the ball and push its opponents off the platforms. A player who falls off a platform (either because they missed a jump or because an opponent pushed them off) or gets hit by a ball is “out” and can’t participate until possession changes and the two teams trade offensive and defensive roles.
Whenever the ball hits the ground (including when the player holding the ball touches the ground), possession changes - unless the ball hits the ground after a successful throw at an opponent, in which case the offense keeps the ball. A team wins if all its opponents have been knocked out of the game at the same time.
Jumping between platforms and shoving opponents use the usual D&D rules.
Throwing a ball at an opponent is a ranged attack, and every non-goliath player takes a -4 penalty for non-proficiency because it is almost impossible to get used to the misshapen goat-ball.
Throwing a ball to an ally is likewise a ranged attack, except that Dexterity bonuses and penalties are reversed when calculating the target's AC (in other words, it's easier to throw the ball to a dexterous target, and harder to get a clumsy teammate to catch it). (Replace with Dexterity saving throw rolled by recipient?)
To attempt an interception, you must be within 5 feet of the ball's path and get a better result on your ranged attack roll than the thrower got on their ranged attack roll. (Better Dex saving throw?)
Also, because the players aren't fighting, they can share the same platform (and often the same square) without penalty.