when you're researching cults and witchcraft:
Interacting with Cults
Witches and Wicca
Some guy who thinks he can fly and that black magic is all in good fun
I've also got a book on the way, as our local library is fresh out of books on the history and workings of witch craft (seems that someone always checks it out and doesn't return it).
Also I'm currently researching the workings of the FBI and would love to take a tour of an actual (big) office instead of relying on my imagination and pictures of the outside of their buildings. Naturally there aren't too many pics of the inside of these places on the internet. However I think I'll have to trust Google and what I can find in books.
I'd also like to spend time with a cult, but something tells me that even if there was one nearby, they certainly aren't going to be enthused about my using them as inspiration.