This is a great article posted on another site (who reposted it from another site, who took it from another), but I thought many would enjoy it here. It is The Lazy Man’s Guide for Constructing a Call of the Cthulhu Adventure, written by Sandy Petersen, original author of the Call of Cthulhu.
On a certain continent, nearly all kingdoms worship under the same pantheon. However, in the southern reaches the peoples take a much more...liberal stance on their Gods. Statues are nude, and very anatomically correct, and icons are often startlingly brazen. For instance, the icon of (insert name), the goddess of love, is an image of two nude twins embracing in a passionate kiss, signifying the love of both family and partner. This is a source of unending outrage and offense for the Northern churches, whose traditional and modest take on religion is constantly at odds with the near-blasphemous ideals of the Southerners. While this is not enough to provoke outright conflict, there is more than enough simmering discontent and long-held grudges between the two hemispheres.