Architectural Foundation's river tour
 

Yes the Architectural Foundation's river tour is recommended, however, it is truly a summer event, unless you want to spend the time in and out of the restroom sharing the heater with others on the same in and out rotation! It was even too cold for my other half to drink a beer . . . that, my friends, is cold. Definitely do this, but do it in the summer.

zackly.
When it was Marshall Fields it was a wonderful place to eat, but now that the carpetbaggers have taken over, fergeddaboudit.

Lakefront
 

I'd add several activities along the lakefront to this list:

Play Volleyball on the beach (hundreds of courts filled with thousands of players on a nice summer after work)

Jog the Lakeshore path

Bike the length of the city

Warm summer afternoons, the bike/walking path is an absolute zoo, but it's fun to be on. The scenery is absolutely beautiful, as well as the _scenery_ ;)