i grew up in chicago, but i live about 1 hour north now. there's plenty to do, i love the museums there (art museum, science & industry museum & the field museum) they've also recently reopened the shedd aquarium, its an awesome place. lots of good places to eat, hard rock cafe, the chop house, the 95th floor etc. they have a tour about al capone & the st. valentines day murders. of course there's the sears tower - awesome views and the house of blues and navy pier. you name it, it's there to do. you should visit the chamber of commerce website for chicago and request a visitors guide, it's loaded with info. be safe and keep your guard about you, best to stay with another person or group of people, if you have to carry a purse, make sure you can sling it across you (under a jacket preferred). oh yeah, don't forget about the magnificant mile of shopping!! it's easy to spend lots of $$
i hope you have a wonderful trip and enjoy our city.