The second rule of Fight Club is: You don't talk about Fight Club.
So I'm going to have to break the rules a little.
In Fight Club, Brad Pitt plays Tyler, a man who makes soap for a living. Edward Norton plays someone who is called simply "The Narrator". When the two men meet on a business trip, things will never be the same again.
Fight Club is a film about people who realise that they have been brainwashed all their lives. They finally understand that they have been living in a rat-race, working a third of their lives so that they can buy stuff that they don't even need. They, like all of us, have been brainwashed by the media, by family and friends, by society itself, into believing that they need lots of stuff, so that they will go out and spend their hard-earned money on it. This is not just a movie plot, this is a fact of life. We are consumers. We are required to be consumers to keep big companies in business. Much of what we spend our money on is garbage, stuff that we could quite happily live without. We're crazy. And when the characters in the film realise this, they are angry. They want to hit back. They want to hit someone, anyone, to get their anger out. They start by hitting each other, in an illegal underground fighting club, but soon they are hitting back at society, and forcing innocent people at gun-point to look more closely at the lives they are living. And at this point I stop agreeing with them. They take their rebellion to such an extreme that they become like mindless fascists, and Tyler's philosophy spawns a nationwide anarchic movement of thugs. Anything taken to an extreme is bad, even what Tyler calls "Enlightenment".
I abhor violence in real life. It's an unpleasant fact of life that I try to avoid at all costs. In films, I will tolerate it because a film is usually a story about people and I am interested in the people. This film has caused an outcry in the US because of the intensity of the mindless violence it depicts. By concentrating on the violence they are missing the point. You could cut most of the fighting scenes out and the film would be just as good and just as clever. In fact, it would probably be even better. Fight Club is not about fighting, it is about mass insanity. I'll leave it up to you to decide who is insane.