Judge Dredd is both the title character of a comic strip running in 2000 AD, and the title of a movie, three RPG's, and a magazine. Set in the 22nd century, most of the united states is wasteland due to a nuclear holocaust. Mega City One, comprising much of the Atlantic Seaboard of the United States, is under judicial law, and is one giant urbanization of oversized buildings, with the judges having taken over the police action as well. Justice is swift; sentencing usually immediately upon arrest.
The setting is grim, quirky, and filled with bad jokes and tributes to famous people. The various RPGs are best noted for being able to play one of Mega City One's elite Judges, to go forth and dispense justice without mercy, and rid Mega City One of perps, with a minimum of high tech gear, and a maximum of Chutzpa.
Each of the three games is a variation on another published ruleset.