You could go see the Frank Lloyd Wright house in Hyde Park and walk around the UChicago campus while you’re down there. Though it might be too cold to enjoy it properly.
Yelp reviews are always a good course when picking a restaurant.
At your hotel, get a free copy of Concierge Preferred magazine. I draw the maps.
Do a Lake Shore Drive & L round trip. Take the Brown Line from the Loop to Belmont, and transfer across the platform to a Red Line train going north to Howard. At Berwyn station, you’ll find a #146 bus waiting downstairs that will go past lakefront apartment buildings for about a mile, then run express via Lake Shore Drive to Michigan Avenue. (Brown Line to Damen and the #145 bus back downtown is a little more interesting but due to recent route changes now involves some walking).
The #146 bus is the tourist’s friend, as it runs from the Mag Mile to State Street and then out to the Museum Campus. The CTA Map is also my work; you can get one at any L station.
Obviously I have asked the right people. 
Dinner on Friday/Saturday night: It will almost always be crazy-hard to find a seat without a long wait or making reservations. Plan ahead, or get help from the concierge.
Robie House is under renovation but entirely worth it. I liked it better than the Home Studio. If you do the Home Studio make sure to take the neighborhood tour.
Dung Beetle, my girlfriend is a tour guide at both of these sites. If you decide to do either let me know and I’ll see if you can get a personal tour.
This is the best advice in this thread so far. To really see Chicago, you must get away from the Loop.
Mr Downtown - I cant believe you did the CTA map! This will probably make me sound lame, but I’m a fan. I love those maps. Did you do the map posted inside the trains?
I’ve lived in Chicago for about 7 years now (well, now in Evanston) and the home studio tour is one of my favorite “touristy” things I’ve gotten the chance to do while I’ve been here.
Awww, thanks!
Keep an eye out for the Cash Cab. Yes, there’s one in Chicago now.
Oh hell yeah! 
Not to hijack, but can any recommend a good boat tour? I’m hoping to take my parents on one this summer as a mother/father’s day gift.
Do you mean a big boat out on the lake with food and stuff, or a river see-the-sights tour? For the latter, I have to recommend (as mentioned above as well) the Chicago Architecture Foundation boat tour. The guides are really good; I’ve been on the tour three times with visitors, I think, and they liked it as well.
Eat an Italian beef. Check that, eat several Italian beefs.
I would step over my own mother for an Italian beef.
Loved the menu at Everest. BTW. I’d love to go there. Hell, I’d live in Chicago in a heartbeat if it weren’t for the weather (California weather wimp I am).
Yeah, the on the river tour. Other than driving by on the way to my place, Idon’t think they’ve been to downtown Chicago in 10 years.
SkyDeck is neat.
I do like Giordanos.
Lincoln Park Zoo
AIC - you could spend a month there.
The planetarium and museum of natural history are nice, and the T. Rex is impressive.
Do a boat tour.
Both Robie and FLW studio are visit worthy, and in Oak Park there are lots of FLW related homes.
Spend some time on the lake - you can basically walk all the way from Navy Pier on one side to the Adler complex on the other.
Yes, there are many fine restaurants in Chicago. But the truth is that you can go to many fine restaurants in several other cities. What you can’t get anywhere else is Italian Beef like they do it at Al’s Beef on Taylor Street, or gyros like they do in lots of non Greek town spots, such as Dengeo’s in Skokie or CrossRhodes in Evanston, or many of the little neighborhood spots. If you’ve never seen a great, classic university campus, the University of Chicago is a great trip. (The big green space called the Midway Plaisance that runs along the campus is where the 1893 World’s Fair was held - a should see.)
and like that
The official Chicago Architecture Foundation architecture cruise is $32, and helps support the foundation. However, the other tour boat operators also have river architecture cruises with excellent guides. I give a lot of architecture tours and have been particularly impressed by the main guide for Wendella.
Since you will be visiting Millennium Park, walk across the street and visit the Chicago Cultural Center (cross Michigan and enter on Washington). Make sure to walk up to the third floor. The interior alone is worth the 10-minute investment, and they may have a lecture, art or music event that might interest you.
I have this weird thing which happens to me when I see a thread title: sometimes it reminds of the line to a song:
Have fun, DB!
Quasi
Yeah, but they don’t have Alinea (generally regarded as one of the top restaurants in the world. Note that that list calls it the best restaurant in North America.)
Agreed about Italian beef. If you came during the warmer months, I’d say no trip to Chicago would be complete without a trip to Al’s, and then across the street to Mario’s Italian Ice. Unfortunately, Mario’s won’t be open yet for Dung’s trip.
While we’re taking the junk food angle: Maxwell Street Polish sausage. Right off Roosevelt and I-94 on Union there’s Jim’s Original and Maxwell St. Express Grill practically next door to each other. For about three bucks and some change, you can get a big, fat, flavorful Polish sausage smothered in greasy onions and mustard. Jim’s is the nostalgic favorite, but I prefer Express Grill’s Polish sausage personally–at least I did the last time I did a side-by-side comparison. Have your own taste-off and grab one from each. The price includes fries (although they usually suck. When they’re on, Jim’s has the better fry, I will admit.)
Also, Chicago is well-known for its regional Mexican food, its Eastern European (usually Polish, although Lithuanian and Czech/Bohemian joints are still around), and there’s a very good stretch of Thai along Western between Montrose and Lawrence (Spoon Thai, Sticky Rice, Opart Thai, and Arun Thai [a mile west on Kedzie.]) Those are the three ethnic cuisines I’d say Chicago is particularly strong in, although there’s wonderful Korean, Indian/Pakistani, various types of Chinese, etc., as well.