A Role-Playing Game, or RPG are originally derived from traditional role-playing games, especially Dungeons & Dragons, and use both the settings and game mechanics found in such games. The stories featured usually involve a group of characters (a party) who have joined forces in order to accomplish a mission or "quest". Along the way, the adventurers must face a great number of challenges and enemies (usually monsters inspired by fantasy, and, to a lesser extent, science fiction and classic mythology). See http://en.wikipedia.org/wiki/Role-playing_game