How to teach improv?

In the past few years I have found myself stumbling into a fair amount of teaching -- at the Steel City Improv Theater and more recently at Carnegie Mellon -- and I've never been taught how to teach. I've never read literature or student-taught or studied different learning styles (which grinds the gears of the real teachers in my family).

With both software (how to write good software) and improv (how to do fun meaningful scenes more often), I find a similar problem: the masters just have a lot of experience. There are different schools of thought and most of it has nothing to do with learning rules and following them. It's a lot of context-sensitive applications of that experience. 

So how do you teach something that comes down to experience? There have been many discussions at the theater about this. While there are definite subtleties, I believe the philosophies break into two fundamental camps:

• Start with the basics: yes and, physical/object work, who/what/where, pattern/game. These are the lingua franca of improvisation that allow you to talk about early scenes. The theory is that learning the basics allow you to understand what you are doing when you transcend the rules. But: is it possible to lose the forest for the trees?
  
  
• Start the way you want to play. If you believe in true emotional connections, comfort and honesty, start there. If you believe in pattern and game, start there. The theory is that by doing good work students will discern the "rules" for themselves -- or their own rules -- and learn to follow their fun. Mick Napier was an early pioneer of this idea, and it has been wholly embraced by folks like Chris Trew of The New Movement (where they don't teach suggestions!). But: is it possible to feel overwhelmed and lost when you start at the end?

I don't believe there is one correct answer. I have been shifting more toward the latter approach but I find a lot of value in the former when coaching and with some groups of students.  

If anyone knows more than I do about teaching, or just has experiences to share -- I'd love to hear your thoughts.