We did this a couple of years ago it was very cool so let's do it again. The Fox Theater (which is an amazing building) has tours on Saturdays at 11:00am. They tell about the history of the building, the architecture, and go back into the ballrooms.
Cost for the Fox tour is $10 for adults and $4 for students. Tours start promptly at 11:00am so we'll meet at the theater entrance at 10:45.
Here is a link: http://www.foxtheatre.org/tours.aspx