Last visited: July 2011 (4 days)
Places to stay:
You'll most likely wind up either on the Magnificent Mile or in the Loop if you're staying in a hotel. Both areas are great, you can easily get around by transit or walking and a lot of the main tourist attractions are nearby. Unlike other cities, where staying in a main tourist area kind of sucks (ahem, NYC Times Square), staying in this area is actually really nice in Chicago. The lake, river and Grant Park are all within a few minutes walk, at most, so it's pretty awesome. Alternatively, you could stay in a bed and breakfast in one of the other neighbourhoods where it's a bit more residential. My pick for a residential area would probably be Wicker Park, it's a nice contrast to the Magnificent Mile / Loop area. If you need a cheap place to stay, the HI Chicago is by far one of the nicest hostels I've ever stayed at. For a fraction of the cost, you're getting a location which is better than many hotels (the hostel is basically across the street from Grant Park). It's clean, they have cheap or free tours, tons of discounts, good security. Shockingly good really.
How to get around:
Pretty basic, just take the L (elevated trains - although, they do occasionally dip underground). Both Midway and O'Hare airports have an L line stop but if you want to take a taxi, FYI Midway is way closer to downtown than O'Hare. The only tricky thing about the L is that the various lines will often have stops with the same name. So, for example, the Kedzie-green stop is nowhere near the Kedzie-orange stop. Buses are also straightforward and I found that the CTA employees were all pretty helpful in giving directions.
Taxis aren't too pricey and are useful for getting around since Chicago is a bit spread out. A car can also be helpful depending on where you're going.
Things to see:
Museums - The Chicago Museum Campus is ridiculously good. I loved visiting as a kid and on my more recent visits always wished I had more time in the city to explore. In that area you have: the Shedd Aquarium; the Field Museum and Adler Planetarium. Right at Grant Park you have the Chicago Art Institute (Love Ferris Bueller's Day Off? Want to try and recreate it? You're not the only one!). There's a lot more museums, but these should get you off to a good start.
Navy Pier - This is so cheesy and crowded, but it can be fun. Especially if you're with friends and rent a bike car thingie.
Boat rides - Oh man, you have to do this! There's like a million of them, just go with whatever, they're all pretty much the same. You just want an excuse to get on the river (bonus if your tour gets you onto the lake too). If you don't see Chicago from the River then you don't deserve to be in Chicago. I went to the Chicago Visitor Center and they have a ridiculous amount of information, including information on like, every single boat tour in town.
Grant Park / Millennium Park - You'll be here at some point or else you haven't actually been to Chicago (seriously, you may actually be in a different city, you should check). Not only do they have an array of events running year-round, they have ridiculously awesome art installations. If an art installation was my best friend, it'd be the big silver bean (don't worry, you'll find it, it's kind of hard to miss).
Tall buildings - Here's a sneaky trick we discovered by accident. Go up to the lounge in the John Hancock building and go to the bathrooms. Best views ever! And obviously, if you're recreating Ferris Bueller's Day Off, a stop at the Sears Tower is obligatory.
Sports - Hell, even if you're just walking past Wrigley Field it's pretty cool to see it. For a schedule of sporting events, why don't you try googling, hmm?
Got the blues?
Kingston Mines - This place is awesome, two stages and a blues band always on.
Green Mill - Al Capone's old speakeasy, the space is great and they're serious about jazz. Like, "no talking while the band is on" serious.
There's a ton of places to go out at night in Chicago. Blues, jazz, comedy, miles of bars - you name it, it's there. And it's fun! Be prepared to stay out late. My nights in Chicago always seem to run longer and get more out of hand than anywhere else (Well, the company I keep is partially to blame ;) but everywhere I've gone has always been fun. We even wound up on a posh rooftop bar that was packed and it was still fun and not obnoxious.
If you want a good drink, head over to the Violet Hour. Possibly the best pseudo-speakeasy in North America (Is it bad that this is something I feel qualified to judge?). I'm not going to tell you exactly where it is, you can figure it out for yourself. Great drinks, super friendly bartenders and doormen and unlike most pseudo-speakeasies, the interior is actually quite pleasant and spacious. Beer drinkers, check out the Map Room; the beer list here drove my friend to making happy squeaky noises.
Deep-dish and more:
Chicago is an amazing food city. I'm going to ignore deep dish because I'm not really a fan. The alternatives are so much better. Italian beef sandwiches are amazing (I think I went to Al's for mine). Chicago-style hot dogs are ridiculous (I don't know where The Wieners Circle is but when it's 3:30am and you're confused, tell the taxi driver to come here, he'll know where to go). Hot Doug's is....Mecca for encased meats? Read more about it here. And Mexican food in Chicago is really good.
For high end, the obvious choices would be Alinea or Next (if you can get a reservation). Aiming a bit lower, any of Rick Bayless's places are worth a try. I went to Mexique for brunch and liked it better than the brunch at Frontera though. Schwa is fantastic! Highly recommended if you can get a reservation, I still think about dinner there...rabbit and strawberries?! (this is an awesome Schwa-related article) General consensus also points to Paul Kahan's restaurants as being very good.