Scientology is pretty frightening. The whole thing started as a gag when L. Ron Hubbard was a struggling science fiction writer. He and his writer buddies were tossing around ways about how to make a million dollars and keep it. So someone jokes, "Why don't you invent a new religion?" and the light bulb goes off above Hubbard's head.
The first Scientology converts were science fiction fans, which I think is hilarious. (And I say that as someone who's read my share of SF.) Remember William Shatner on Saturday Night Live? "Get a life, will you, people?"