Diplomacy
Diplomacy is a strategy board game that situates the player in Europe in 1901 with the goal of conquering the Continent. Each player is in charge of the armed forces of a major European power and must decide which battles its various units should fight.
Diplomacy is played by 7 players that compete but that also have to co-operate to be able to win. Players secretly negotiate to settle alliances. They select whom to ask for help, argue to get information about other agents' goals, and so on.
All the game is about building trust and reputation, maintaining relationships, negotiating deals, arguing with the aim of persuading other players,...
The following video was created to introduce you the Diplomacy Game. For more information and the complete rule book of the game, take a look at http://en.wikibooks.org/wiki/Diplomacy.