We recently tried a Lovecraftian version of The Underdeep (a dungeon crawl game using Mana Press' Tribal rule system).
The game uses adventurer archetypes (mage, archer, thief, warrior, cleric etc...) which became their early 20th century equivalents ( arcanist professor, shotgun dame, ruffian, police officer, priest..). They fought off deep ones and cultists in chaotic labyrinth somewhere in Massachusetts. The Professor found the Necronomicon, but forgot the last of the magic words needed to release it... instead releasing an otherworldly horror. The priest managed to escape with the book, but the interdimensional rift was left un-sealed..........