I play from a series that's not just 7 books long on its own, but has 2 additional canon sources, and ties in to at least a dozen other works by the same author. I love the series and I will happily reread it for fun and not just to canon review, but it's a lot to ask for most people. And while I do occasionally see other Dark Tower players out there, I don't really expect to see them often because it's not something most people can just jump into.

Of course, I've heard talk of a movie adaptation for many years now and while part of me would love to see it, I wouldn't want to play with a sudden influx of movie RPers. Also, I have yet to see a Stephen King adaptation movie that wasn't disappointing on some or all levels. But that's a different issue.