Forgotten Realms a hoax? Don't even try to tell me that Elminster isn't real.
Anyway, lots of people seem to think that the Necronomicon is real. I suppose that's a credit to the influence that Lovecraft's work wields, so many years after his death.
I would imagine that many a pseudo-Occult weenie can be seen furtively stuffing a copy of the Necronomicon into his locker. I dunno about you, but if I was looking for a book of Unspeakable Evil, Waldenbooks wouldn't be the first place I checked.
I could use a helper-Shoggoth though. The helper monkey is soooo overrated.