The objective is for everyone to throw their ball up in the air and catch a different ball without a single one touching the ground.
You may want to divide into smaller groups for this game. Every person in the group has a ball.
Standing in a circle or cluster or however the group wants to arrange themselves, they must throw their ball up (over a metre or 2 up) and then attempt to catch a ball they didn’t throw. The number of balls that hit the ground is that group’s negative score. The goal is to score zero in a single round.
Allow the group to work together to achieve this. It will be pretty difficult and the group might need lots of time or multiple sessions to accomplish it. A variation is to have the group start with only one ball thrown and caught.
Each time they successfully catch a ball, another is added for the next round until they drop one and then the whole thing starts again.