Chicago, eh? I lived there for three years due to the life of a Navy family(transfers and moving), and it is a very nice city

. If you two have much downtime, there are a few hotspots to see:
Museum of Natural History: Not only are dinosaur bones there, but many other exhibits exist, such as cavemen living conditions, witch doctors' practices, gems and unique rock formations, and perhaps some other exhibits.
Shedd Aquarium: Lots of wildlife

. They even have penguins, dolphins and beluga whales.
Museum of Science and Industry: Lots of history on industry. They even exhibit some of the original Ford models from the beginning of the twentieth century.
Shopping: Michigan Avenue, Magnificent Mile and the historic Water Tower(one of the few surviving original buildings after the Great Chicago Fire) are all great places to shop. If I remember correctly, the tower has at least eight stories, and there is access to FAO Sweetz, the world's largest candy store

:. That brings back fond memories of Christmas shopping downtown

.
Oh, yeah. Don't forget to go to the top of the Sears Tower. The view is beyond the imagination.
One final and very important pointer: Have fun, and brace yourselves when walking. It really is windy there

.