A favourite party game throughout my high school life. Produces readily quotable and hilarious results.

Overview

In this game, the objective there are citizens, mafia(s) and an inspector. Each group has a different responsibility and goal. There is also a god who decides who is who. This game works best when participants are not drunk, as well as for 6-12 players.

The Game

The game begins with everyone closing their eyes and God choosing mafia(s) and an inspector.
God says: One tap mafia, two taps inspector and goes around the circle tapping people.
One inspector is chosen, and 1-2 mafia depending on the size of the group.

After the tapping is complete, God tells the mafia(s) to open their eyes to acknowledge each other, then close their eyes. The inspector is then instructed to open their eyes to ensure he/she realizes their position.

Everyone is then instructed to open their eyes. The fun begins.

The citizens are trying to figure out who the mafia are by accusing members of the game of being the mafia.
The mafia are trying to mask their identity while accusing others of being the killers.
The inspector is trying to figure out who the mafia are, yet keep their own identity hidden.

After a round of arguments is complete and by majority vote someone is accused of being a mafia, God reveals the identity of the accused. If the accused was a citizen, the citizens have guessed incorrectly and have lost a member of their contigency to the evil mafia. If the accused was a mafia, the citizens have either a) won that game because there was only 1 mafia or b) won that round because 1 mafia remains. God then instructs everyone to close their eyes.

After the first round, if the game is to continue, the following instructions are said.
Mafia, who would you like to kill?
At this point, the remaining mafia open their eyes and point at who they would like to kill. The mafia close their eyes.

Inspector, who would you like to know?
The inspector is then allowed to point at someone they suspect is mafia and God reveals the chosen one's identity. The inspector opens their eyes.

God reveals who the mafia killed that round.

This cycle continues until a) the mafia have killed everyone and have won, or b) the citizens have killed the mafia.

Advanced Strategy

Many different strategies exist that are too complicated to be set down in words. They emerge from consistent game playing and thinking. Most involve lying, picking on someone or telling the truth.

This game is extremely amusing when played correctly. I am a witness to this fact.

Addendum

There also exists variations to this game, one of which is the introduction of the medic or doctor. This player is chosen by God in the same manner the mafia and inspector are chosen.
The medic is special because he/she has the ability to save players. At the end of each round, after the mafia has designated someone to 'kill', the medic opens his/her eyes and designates someone to 'save'. If the person to be killed is the same as the person to be saved, nobody dies in that round, and the medic now knows who isn't mafia. If the medic chooses the wrong person, then nothing happens. The medic has the ability to heal him/herself.