Ringworld

The Ringworld science fiction role-playing game was published by Chaosium in 1984, using the Basic Role-Playing (BRP) for its rules and Larry Niven's Ringworld novels as a setting.

The players initially play explorers from Known Space, sent as scouts to the Ringworld. They can be anthropologists, artists, doctors, police, or even zealots, who will explore the mysteries of this huge artificial world and its inhabitants. Basic characters can be humans from a dozen planets of Human Space, Puppeteers, or Kzin. Later play can see characters from Ringworld species, such as the (so-called) Ghouls, Vampires, Giants, Sea People, and others.

This Ringworld focus has been a criticism of the game. The Ringworld role-playing game is not a 'full' science fiction RPG, like Traveller, including, for example, rules for starship construction, space combat, travel to different planets and systems, and so forth. Instead, the game and rules focused on parties of characters exploring the Ringworld itself, and, despite its vast size (in many ways larger than the rest of Known Space put together), many who bought the game felt limited by this one world setting.

Source: Wikipedia, "Ringworld (role-playing game)", available under the CC-BY-SA License.