Guyana-Cult of the Damned has crawled out from under a rock and into local theaters, and will do nicely as this week's example of the depths to which people will plunge in search of a dollar. The movie is a gruesome version of the Jonestown massacre of 1978, so badly written and directed it illustrates a simple rule of movie exhibition: If a film is nauseating and reprehensible enough in the first place, it doesn't matter how badly it's made - people will go anyway.