Retro RPG: Cosmic Encounter
Not an RPG at all, but a board game, but it's a geeky one, so it counts.
Cosmic Encounter is a science fiction–themed strategy board game designed by "Future Pastimes" (collectively, Peter Olotka, Jack Kittredge and Bill Eberle, with Bill Norton) and originally published by Eon Games in 1977. In it, each player takes the role of a particular alien species, each with a unique power to break one of the rules of the game, trying to establish control over the universe. In 1992, a new edition of Cosmic Encounter won the Origins Award for Best Fantasy or Science Fiction Boardgame of 1991 and placed 6th in the Deutscher Spiele Preis. The game was inducted into the Academy of Adventure Gaming Arts & Design Adventure Gaming Hall of Fame in 1997.
Cosmic Encounter is a dynamic and social game, with players being encouraged to interact, argue, form alliances, make deals, double-cross, and occasionally work together to protect the common good.