I got a book out of the library called Combat Mime, about doing stage combat, figuring that the techniques could be reworked for film. It caused me to do two things:
First, I bought the book. It was that good!
Second, I decided to do a series of videos demonstrating some of the techniques. I see amateur filmmakers all the time trying to do a fight scene, only to have it look cheesy because they're being gentle. These videos (and the book) will show how to spice up those fight scenes and make them look real.
Visit http://phantommoose.com/2008/06/18/great-resource-combat-mime/ for more.