To get things done, an investigator needs to repeatedly break the law.Very seldom does this requirement fit with the investigators being played. We have librarians, lawyers, authors, accountants, some crooks of course, but still ... the logical thing for investigators to do when faced with horrible things should be to go to the authorities. And if we play crooks and bad guys, why should we get involved in the first place? Of course, it is possible to structure a Call of Cthulhu game so that this problem does not occur, for example by isolating the investigators in a backwards mountain area, which I have done on several occasions, or put them on a time schedule, or other such tricks. But after playing Call of Cthulhu for 24 years or so, this becomes a tad bit predictable.
So I'm going to try something different. I'm setting up a campaign I'm tentatively calling Cults of Cthulhu. I'm going to turn the tables on the premise and let the players take the role of cultists. I think this can be as fun as playing investigators, and a real kick to get to think as the bad guys do. And have all the problems that bad guys do, with the authorities, investigators, insanity an rivalling cults. Because just like the investigators, the cultists loose their sanity, they get embroiled in things they know nothing about, the meddle in magic, they take enormous risks ... but for them, all this has a purpose, unlike for many investigators who would rather call the police and curl up under the bed, praying to an uncaring and probably non-existent God.
The purpose of the cultist makes their actions seem logical and beliavable..And the premise neatly explains why you can't call the authorities, and why you must avoid the police, the clergy, the investigators, the enemies of the occult ... or of the cult, as the case might very well be. Another great thing is that it is possible to use the same adventures as always, with only minor modifications: the cult is to be protected and strengthened. Find out who stole the artifact from the museum, because you want it for yourself! Who killed the old librarian, your cult mentor? Stop the cult from raising Nyarlathotep, because you want to do it yourself! And so on, so forth.
I'm sure I'm not the first one to try this, so weigh in with with your thoughts and tips in the comments!