Storm the castle
Storm the castle is a fighting game for two groups of at least 4 or 5 players each.
You don't need any equipment to play that game.
One group is standing in a circle, they hold each other's hands. This represents the castle. The other group is outside. After the starting signal, all the players outside try to get inside. The time is taken how long it takes to bring all the outer players inside.
Of course, you may not get to violent. While pushing and pulling is allowed, smacking and kicking isn't. The referees have to enforce the rules and take players out of the game who get too brutal. The players already inside the castle may of course help those outside.