Inspiration for planetary adventure role-playing can not only be found in the fiction of authours such as Edgar Rice Burroughs or Leigh Brackett, but also in fringe beliefs, pseudo-science and out right hoaxes. One such source of fantastic imagery is the Great Moon Hoax. This was a series of six articles published in the New York Sun in August 1835 reporting the supposed discovery of life and civilisation on the moon. The discoveries where falsely attributed to Sir Jon Herschel, one of the best known astronomers of the time. The articles described various alien flora and fauna, including unicorns, bipedal beavers and bat-winged humanoids (“Vespertilio-homo”), and buildings such as a mysterious structure believed to be a temple.
This charming lunar romance is not only filled with ideas ready to be inserted into any planetary adventure campaign but could very well be used as a game setting in itself – the PC’s could be human explorers arriving to the moon by balloon as in Edgar Allan Poe’s “The Unparalleled Adventure of One Hans Pfaall”. HG Wells “First Men in the Moon” provides a sublunar empire of insectoid selenites for underworld adventures.
You can find a detailed account of the story, along with the original articles and many images here.