What we could do is like a tag kind of game
You can bring any weapon you want and whoever is it you have to tag the other person, the other poeple just try to avoid him, when the timer runs out whoever is it will lose and is out of the game, then we play the game without him intill we have a winner the time limit per game should be about 5mins? anyways the reward should be, erm.... a promotion? =D that would get peeps to play.