10+ people, no equipment required.
One person serves as administrator.
Everyone else sits in a circle. Randomly, secretly assign 1 investigator and 2 Mafia. (Playing cards work well for this.) Everyone closes their eyes, and the 2 Mafia silently tell the Admin who they want to kill. After the Mafia close their eyes again, the Investigator silently asks the Admin whether someone is Mafia (by pointing, the admin nods yes or no) Everyone opens their eyes again and the Admin informs the victim that they are dead. The victim leaves the circle. All surviving players debate who might have killed that person. Survivors vote who they think is one of the Mafia. Majority rules. The accused is "executed" and leaves the circle, then reveals whether or not they are Mafia or Investigator. Everyone closes their eyes and the game continues until both Mafia are executed or everyone else is dead.