While real-life fight clubs occasionally pop up all over the world, from Russia to Delaware, they don't actually seem connected to the film in any way, aside from the media's tendency to brand them as "fight clubs" so they can use screenshots of Brad Pitt's abs to drive traffic to websites. These fight clubs seem to be put in place just for men to fight, and not necessarily to explore the anarchistic values of the film.
Slash and Burn
Also, because this movie deals with men stripping down and grappling with each other, there's a small slice of the internet devoted to slash fiction (which is often male-on-male fantasy action between two characters in a popular work, in this case Jack/Tyler—see the slash?)
But wait: if Jack and Tyler are the same person…does this mean these slash fic writers are just fantasizing about Tyler having sex with himself?