Open House Chicago
 

Chicago Architecture Foundation is running an event this weekend with behind-the-scene tours of a ton of interesting buildings (and it appears a few not-so-interesting buildings). Could be worth checking out.

http://www.openhousechicago.org/

I visited several of the sites in the Uptown area. It was a very pleasant afternoon: not crowded and you explore some beautiful buildings at your own pace.

If this is an annual event, I would highly recommend taking advantage next year.