History of live action role-playing games
Live action role-playing games, known as LARPs, are a form of role-playing game in which live players/actors assume roles as specific characters and play out a scenario in-character. Technically, many childhood games may be thought of as simple LARPs, as they often involve the assumption of character roles.
Source: Wikipedia — History of live action role-playing games (CC BY-SA 4.0)