For this game you’ll need plenty of Nurf balls, Gator skin balls, or some kind of ball that can be held in one hand and wont hurt when you hit someone with it.
Play in a big open room like a gymnasium or a fellowship hall. If you have the kind of tables with the folding legs set a few of them up by setting up one side of the table legs so that they can be placed in an upright position to make a sort of hidding base. Spilt your group in to two teams and give each one a “tag ball”. Start them on either side of the big room. The object is for one team to eliminate all of the other team. When a person is hit they are out. A player can only carry one “tag ball” at a time. Thrown balls are fair game for empty handed players. Make up rules as you see fit and have fun.