This is pretty awesome. I was curious if there were any tree house hotels around the world...and what do you know, I found one in Washington state. It's called Cedar Creek Treehouse and it's not too far from Mount Rainer.
In 2000-2002, they added onto the tree house with the octagonal Cedar Creek Treehouse Observatory that is 100 feet high. There is the spiral "Stairway to Heaven" staircase is 82 feet high and connects to the "Rainbow Bridge" to the Observatory.
Just in 2010, they added yet another aspect to the treehouse. During the summer, they added the "Sun Bridge," that is 68 feet long and connects to a floating web platform. This platform is to support another treehouse they plan to build this summer.
Guests are able to enjoy the view of Mount Rainer and Mount Wow.