What are fun things to do in Chicago for 17th birthday?

It will be my birthday this saturday and i'm turning 17. My friend and I want to go to Chicago and shop, so it will only be the two of us. What else is fun to do besides shop? We've already been to Rainforest Cafe, Ed Debevics, Navy Pier, and Dave and Buster's enough times to puke, so do you have any 'secret hot spots' that you'd like to share with me? We aren't old enough to go bar hopping (sadly,) but whatever we do pretty much must be in walking distance from Michigan Ave. since the car will be in a parking garage most likely. Thanks so much!