No car needed. Great walking city and great public transportation.

Baseball Fans? Take a look at the Cubs and/or White Sox schedules to see if they are home.

Highly recommend the Chicago Architecture Foundation Boat Tour. They also offer a lot of walking tours..

Go up the Hancock Tower and / or the Willis (was the Sears) Tower.

Loved the Field Museum and the Shedd Aquarium

My first suggestion is that you change your hotel. The Hyatt near McCormick is OK if you are going to a convention or a concert BUT it is not a great location for touring Chicago. Next do a quick search using the "search the forums" function for trip reports on Chicago, there are are quite a few and they will give you some ideas.

After you have searched the forums as SAB suggested, ask whatever you are not clear about.
Are you flying to Midway or O'Hare or arriving in town by train?
Depending on where you are coming from, you could leave the city on Amtrak.
I enjoyed the free self guided tour of the Federal Reserve Bank on Jackson across the street from the Chicago Board of Trade.

I agree that the Hyatt McCormick is in a bad location for sightseeing. For what to see/do, check www.choosechicago.com or www.explorechicago.org. They're the city and convention bureau tourist sites.

For restaurants, check www.chicagoreader.com or www.chicagomag.com. You can search by cuisine, price or neighborhood. Both sites also have event listings.

If you're interested in theatre, you can find a listing of shows on the League of Chicago Theatres site at www.chicagoplays.com along with info on what discounts are available.

For transit info, check the CTA site at www.transitchicago.com. You can purchase transit passes at either airport or most CVS and Walgreens stores. A 3-day pass is $14 and allows unlimited rides on all CTA trains and buses.

Last time we were in Chicago we took a Tastebuds food tour. We had a lot of fun walking around the city trying different foods.

With all due respect to the above poster, you do not have to spend $40-50 pp to walk around Chicago, sampling different foods. However, if you feel compelled to do so, I strongly suggest that you fully research 1) your guide's training and background and 2) the places to which you will be going on that tour - for example, look at some reviews of them, critiques either by the general public or professional.

It's exciting to visit a new destination and I know that you'd like to get the most out of your very limited time here. But where to begin? Being a first-timer, you'll most likely be spending the majority of your time "downtown" (meaning, the Loop); on or near the Magnificent Mile (N. Michigan Avenue north of the Chicago River north to Oak Street); the Streeterville neighborhood (each of the Mag. Mile to the Lake); River North; and/or the Gold Coast neighborhoods.

Make two lists - one for outdoor activities and one for indoor. Of course, we are hoping for a beautiful - and early - spring. But nothing is guaranteed and weather can be very changable then.

If the weather is inclement, it's likely that you'll be going to at least one of the major museums, most of which are outside of those neighborhoods. The Art Institute IS located in the Loop and is a gem. The Museum Campus, which lies just beyond the southern boundary of the Loop (Roosevelt Road), contains the Field Museum of Natural History, the Shedd Aquarium and the Adler Planetarium. Of these three, the Shedd Aquarium is certainly the most popular with long to very long lines, especially at times when kids are not in school. The Museum of Science and Industry is located in the Hyde Park neighborhood (where the University of Chicago is also located), about 7 miles to the south of the Loop. Although it is a fine museum, I would not recommend that you go there, at least not on this trip, due to your very limited time - as it is also a HUGE place, which takes most of a day to explore.

However, I hope that you travel a little beyond those limited boundaries. And here is a suggestion for your deciding on what's best for you:

Go to the Explore Chicago website. There you will find information regarding all of the various neighborhoods of Chicago. For the additional neighborhoods (other than the above), I suggest these for your consideration: Lincoln Park (especially if the weather is nice); Lakeview (Wrigley Field is located in the Wrigleyville area of this neighborhood - Boystown is to the east of that and the N. Southport Corridor is to the west); Wicker Park/Bucktown (actually two neighborhoods adjacent to each other); perhaps Chinatown or Old Town.

Then I strongly suggest that you consider using the free Chicago Greeter service. You can choose your tour based on an area, neighborhood(s) or by a particular interest. If you cannot decide or if you should run out of time, there are InstaGreeter guides at various locations around the city. I do want to mention to carefully review their website because, as the year progresses spring into summer, they tend to offer even more types of tours.

Let's talk about evening entertainment...Are you planning on doing anything such as attending the theatre? Going to a jazz or blue club? Comedy club? When you are thinking about this, please note that with the theatre offerings, you can choose either Broadway-style or Chicago-style. With the latter, it is more likely that you will be going to a theatre venue located in either the Lincoln Park or Lakeview neighborhoods (although there are some in the others as well). With the former, you'll most likely be in the Loop Theatre District - however, the Chicago Shakespeare Theatre is located out on Navy Pier.

Totally agree with the Chicago Architecture Foundation suggestion. Still a little too early in the season for the River Cruise, although they might have limited options if the weather permits. Their main location is the ArchiCenter, located across Michigan Avenue from the south end of the Art Institute. They have many tours available - and adding more all the time. Well worth your consideration.

Chicago is a world-class destination for dining. You do not mention your likes or budget - and without knowing where you would be in the city, it's near impossible to make any viable suggestions. So, once you've gotten a general idea of where you will be during your visit, add to this thread and we can make further suggestions.

Oh, that Explore Chicago website I mentioned above? Make sure you plug in your dates to see what special exhibits, concerts, events are happening then. You might find something only happening then that will make the stay really special.

Gosh, my proof reading skills are certainly lacking today. When speaking of Streeterville, that's "east" not "each"

Check out my trip report (the last few posts on the thread contain what I actually did) for Chicago attractions here:

http://www.fodors.com/community/united-states/6-day-chicago-itinerary-feedback-wanted.cfm