Earlier versions of the game were titled GUCS: The Generic Universal Comedy System (a parody of GURPS) and were distributed privately beginning in 1989.
The core systems of Risus owe their largest debt to the Ghostbusters RPG published by West End Games, and to Tunnels and Trolls by Ken St. Andre.
The game itself also cites GURPS as an influence, along with FUDGE, another free RPG released to the web a year earlier.
Risus itself has been translated into Chinese, Croatian, Czech, Danish, Dutch, Esperanto, French, German, Italian, Japanese, Korean, Norwegian, Polish, Portuguese, Russian, and Spanish.
An example of another commercial product is A Kringle in Time, "an adventure about saving Christmas from ancient evil.