Do you do adventure races?

Anyone out there do Mud Runs, Reebok Spartan Races, adventure races and the like?  I'm looking for inputs on how to best train for them.  My gut feeling is a mix of running and functional fitness type training (to avoid certain terms) but would like to hear from you.  Please feel free to post a comment and even leave a link if you run a blog or website helping people prepare for adventure racing.