The best part about standing in the rain for an hour waiting to get through security? Finally freedom to wander the Circle when it is closed to traffic, of course! Our county has a few of these small circles that act as a town feature and traffic calming device.
It also reminded me about some lesser known tutorials in the Civil 3D 2009 help file.
Go under Help>Tutorials. Notice on the "welcome" screen it gives you a chance to get the tutorials in pdf- so you can print out a segment to read on the bus ride home.
Dig in under AutoCAD Civil 3D Tutorials > Advanced Corridor Design Tutorials and see Intersection and Roundabout Design lessons.
Do the lessons, then amaze your friends! Learn how to model roundabouts in Civil 3D. The principles should apply to interchanges, traffic circles and more.
And if you need help navigating the roundabout you just designed, watch this video.