Everyone has fantasies about living in a tree house. I still envision having one someday complete with a bed and an easy chair so I can actually hide out up there for a day or two.
This, however puts my Swiss Family Robinson dreams to shame. The Fab Tree Hab, which is being developed by architects at MIT, takes a handful of saplings and transforms them into a two-story, energy efficient, water recycling haven. The system will take about 5-10 years to grow, depending on your climate, but once it's matured you can insulate it with straw, put up plaster walls and carry on with business as usual. The conceptual drawings make it look a bit like some futuristic bug, but really its just an awesome, creative solution to living in tune with the environment. Or, literally, in the environment.