Shab-al-Hiri Roach is narrative-based and GM-free RPG, which puts it squarely in what has increasingly become my interests. Although I played it before I got into those kind of games :D
In the game, the players are all faculty in a New England university in 1919. Underneath the genteel veneer of polite society is a seething pit of jealousy and rivalry. Over the course of several scenes, the players will engage in social conflicts, risking their reputations in order to increase those same reputation.
Oh, and there's a Lovecraftian roach from ancient Sumeria who can empower and damn the players in its own quest to spawn and spread its malignant influence.
If you accept the roach or are possessed by it, you get some big bonuses. That little Cthulhu cockroach will give you some considerable mechanical advantages. BUT you can't win the game no matter high your reputation is if you are still possessed by the roach. And getting rid of that little eldritch abomination will require luck and sacrifice.
In my one experience with Shab-al-Hiri Roach, just about every last one of us caved in and gave in to the roach. The winner ended up being humiliated and forced to leave the university in shame and disgrace but, by golly, he won because he didn't give in to the temptation of the roach.
It was a hoot.
Shab-al-Hiri Roach Is not one of the great indie games. Fiasco, which is an obvious comparison since it's also by Jason Morningstar, has slightly simpler rules, tighter relationship rules and the flexibility to be used with any setting. Shab-al-Hiri Roach doesn't just tell a specific type of story but a specific story. I'd play it again cheerfully but I wouldn't form a group to play it over and over again.
But it's still a fun game, in huge part due to the theme. For me, it's like a mashup of Lovecraft and Wodehouse (which, I know, has been done plenty of times) The concept, while it could be straight up horror, really lends itself to hysterical black comedy.
I view Shab-al-Hiri Roach as the promise of greater games to come in Morningstar's work but it's still fun on its own.