We found this awesome treehouse, built by the local neighborhood, while looking for an old cache (thanks to FishPOET for archiving the missing "Ugly Cache" and letting us adopt this caching area).
The first stage is the most difficult. You need to climb and look for the well-camoed tweety bird in him hideout to tell you the coordinates to the final stage(s), which have some cool swag.
Each stage involves tree climbing and there is some hiking involved.
Have fun!