Why not have a look at my new blog: passion4games.

Although there are a number of MMA organisations around the world, the Ultimate Fighting Championship is the most recognised.
Over the last few days I've been having a look at some videos of the UFC over the last few days - mostly the compilations of some of the best knockouts. Have a look. It's a shame about the music though. Could really do with a bit of industrial or metal.
Although mixed martial arts competitions do have rules, it is still probably the closest representation of a bar brawl as a sport. It really is fighting by definition.

PS. As a sport, there is nothing more physically demanding than combat sports and martial arts. It is full mind, full body, full threat. It just saps your strength. I should know, I've trained for long enough...