The Darkest House is pretty cool. And, TBH, pretty scary.
The Darkest House is a tabletop roleplaying game (RPG) compatible with the game you're playing now. In fact, it's made for it. Quickly and easily convert your existing characters (it takes about five minutes) and use those stats while in The Darkest House. Once the PCs emerge, your players will return to their regular setting using their regular character sheets. The House System is a sort of RPG Rosetta Stone, allowing easy translation into and out of any game system—and even letting you bring characters from different games together.
https://www.kickstarter.com/projects/montecookgames/the-darkest-house