Tribes

Tribes is a role-playing game that plays a lot like a board game and simulates the way our ancestors lived long ago. The players are cave men and women. They hunt and gather food, make their tribal laws, and deal with natural disasters, but the object of the game is simple: Look after the children! In this game, the way to win is to have the most kids and do whatever you have to do to make sure they survive to adulthood. The players must know when to cooperate, and when to cut their losses and protect their own families. Players can re-create – and change – the earliest human societies by instituting their own laws and social patterns, and see what effects the rules of society have on their ability to survive and reproduce.

With several copies of the game and a referee, it's possible to have several tribes playing at once, competing, trading, exchanging members, and even making war on each other.