The Timber Framers Guild is cutting the joinery and erecting a wild life viewing tower in Danville, Illinois, Sept. 21st -Oct 4.
Here is a drawing of the tower:

To find out more details here is the link to the web page at the timber framers guild web page:
http://tfguild.org/rendezvous/vermiliontower/Join us in America's heartland in the fall for a combination Raising, Rendezvous, and Compound Joinery Workshop to build an observation tower at a wildlife refuge.