Lankhmar (board game)
Fritz Leiber and Harry Otto Fischer contributed to the original game design of the Lankhmar wargame, and Gary Gygax, Robert J. Kuntz, and Brad Stock redeveloped the game for publication by TSR in 1976. The game was originally to have been published by Guidon Games.
The published game is played on a smaller, conventional board, and features elements that had become common in wargames during the intervening years, such as hexagon shaped spaces and randomized combat results (rather than the squares and simple captures of the original version). This is a rare case of a game adaptation written by the creators of the stories the game is based on.
The TSR game is for 2-4 players, each of whom takes a hero (Fafhrd, the Gray Mouser, Pulgh, or Movarl) and leads the forces of one of the powers of Nehwon in an effort to capture the opponents' citadels. This oppositional stance is unusual for the series, though there were a few times in the stories where Fafhrd and the Gray Mouser were temporarily committed to opposing sides. The TSR game is simple and includes bits of color from the series, such as geases that send the heroes around the board chasing various goals at the behest of Sheelba, Ningauble, or various gods.