The always innovative Michael Garnier from my old community of Takilma, Oregon explains his latest creation.
Long ago, living amongst the granola crowd (Nuts and Flakes) Michael gave us Fantasy Flakes which have since manifested in many ways. For Michael, it was to demonstrate the quality of "a life out on a limb" (you gotta see this page so click now).
Here's another video that chronicles a bit of the process of tree house-building. Imagine -- it all started back in the 60's with some simple hippie hovels. No claims made as to whether this qualifies as a model for sustainability but the passive solar feature is a brilliantly simple demonstration of working with nature.