Cults of Cthulhu

Courtesy of Wikipedia, here's a list of all the cults mentioned in canonical Lovecraftian work.
Here's an example of how a cult works in the Arkham Horror game (for a bit of a guide).
Here's an initiation right of the Order of the Golden Dawn.
Here's a list of Masonic initiation rites.

Not that I'm plotting anything related to this for a game or anything.