The Monty Hall problem revisited

This is one of my favorite problems because it always baffles me why its so hard to get to "know" the solution. Every time I come across and read it, it's like I'm seeing it for the first time.  Holding an intuitive notion of the solution always seems to elude me.

I came across it again today. This time on video explained by Keith Devlin who is a wonderful explainer.

http://www.stanford.edu/~kdevlin/Movies/MontyHall.mov

More about Keith, Monty Hall and why some math needs to be learned "top down" - at least according to Keith - coming soon.