I know! How about you do a game thats like a RPG. Except not about heroes! It would be about peasants! The Life of a Peasant! You could call it LOAP for short!
Just kidding.
I'm not sure if this has been done, by why not try an assassination game. There would be assassins, who would be given a target who is someone on the defenders team. The defenders don't know who the target is, and have to defend against the assassins anyway. If the defenders survive X minutes, they win the round. If an assassin kills an innocent (they can hurt innocent though), then the defenders win. If the target dies, assassins win.