I have another abnormal setup: The SPUI (Single Point Urban Interchange)
http://www.kurumi.com/roads/interchanges/spui.html
Split-level Diamond Interchange (referred to abritrarily on one site as a "volleyball interchange."
http://www.kurumi.com/roads/interchanges/volleyball.html
Example of "volleyball interchange"
http://homepage.mac.com/jeffmorrison/June05/us77.html