Chicago...for Adults!

OK...I concur - Second City if you want comedy. It's sketch comedy theater.
Zanies is great if you actually want a show (and down the block from Second City).

For Italian...go to little Italy. It's over by UIC, west of the loop. These are little family italian places, and it's as good as anything you'll get in Italy.

It's summer, so street fests are abundant if you're coming soon. That's the way to really experience the city. Otherwise, get out and see the neighborhoods, don't just stay in the mag mile area.
Go see Boystown, walk around in Lincoln Park and Wrigleyville...
The Southport and Addison is a really nice area for just strolling around and people watching...
Lincoln Square is great for German food, beer and german polka band dancing... (I live in this area)...
Hit the beach and walk around the Museum Campus.
There's a million parks in the city, and they're all really pretty on a fall day.

When are you going? Where are you staying? That might influence what you do. Or how accessible things are.

I also think Second City is good - just keep in mind a lot of it is improv, so sometimes you are like "where did THAT come from" and it's a big quirky.

For "old world mafia style Italian food" Italian Village in the loop is your place!!!! It's fantastic.
http://www.italianvillage-chicago.com/

However, any of the "rosebud" restaurants will also probably fit the bill. Rosebud on Rush is my fave....by my sister likes the one on Taylor St. (Taylor street is a bit south and out of the way for visitors).
http://rosebudrestaurants.com/rest3.php

I prefer the John Hancock over the Willis Tower. You can go up to the 96th floor and just have a drink in the Signature Lounge if you don't want to eat there or pay to go to the observation deck. But make sure you go to the bathroom - seriously. the view is fantastic from the ladies room on the 96th floor. I'm not joking. really.

If the Sox aren't playing... the Cubs probably are... I think they alternate.

If a friend of mine were coming to town here is what I would let them choose from......

* NEIGHBORHOOD FESTIVAL - these are one of my favorite things about the city. When are you going? You can get the list here http://www.chicagonow.com/show-me-chicago/2012/03/chicago...
But I think they only go through Aug, so this would only work if you go in the next couple weeks.

* The architectural boat tour http://www.chicagoline.com/architectural.php

* The Ferris Wheel at Navy Pier (unless you have a problem with heights

* John Hancock Center OR a drink at the Skybarr in the W hotel (pretty much the same view)

* Baseball game Cubs or Sox (you don't have to choose if you're from out of town!!!!)

* Bears game if they are in town (sometimes hard to get tickets for)

* Cafe Ba-Ba-Reeba for sangria and bacon-wrapped dates

* Lincoln Park Zoo

* Jazzin at the Shedd - most Wednesday nights in the summer, but check the calendar.

* Red velvet cupcake from Sugar Bliss (115 North Wabash) - this is right across from the downtown Macy's. it used to be the big Marshall Field's. They have a GREAT brunch at the Walnut Room (7th floor) on Sundays.

*Bicycle ride on Lake Shore path (you can rent a bicycle from either Oak Street or North Ave beach)

* see a movie in the VIP section at the new ICON theatre on Roosevelt (you can get a bottle of wine and order dinner and eat while you watch the movie - the steak sliders are to die for!!!!). Depends on what is playing though. http://showplaceicon.com/NowShowing2.aspx?TheaterID=8146
Make sure you do VIP - otherwise it's just a regular theatre!!!!! Also Parking is free here, which counteracts the insane ticket prices.

Have fun!!!!!!!!!!

If you're into museums - Shedd Aquarium, Museum of Science and Industry

Willis Building (formerly known as the Sears Tower) - They have the new Ledge, where you are standing out over the city and can look straight down at the street. Freaky!

Second City is amazing! They do college tours, so I saw them a few times as an undergrad.

What kinds of things do you want to do?

What do you like? Second City comedy. Art Institute. Millenium Park. Lots of good shows and theater. Shopping? There are great restaurants--the Mexican one (is it Frontierra?) is nationally famous, but has long waits. I don't know if it still exists, but there used to be a very romantic fondue restaurant in Lincoln Park. Do you like other museums? There are many to choose from. A boat ride/architectural tour from the lake. Navy Pier has night life. Rush Street used to be the happening area for partying and the younger crowd. If we have more information about what kinds of things you like to do I can maybe be more specific. If you like sports there is an ESPN Zone bar/restaurant. Wrigley Field, of course, if it's still baseball season.

I would suggest Shedds aquarium and the museum of Science and Industry. Coyote Ugly is there and that is fun to see. Howl at the Moon is a dueling piano bar. If you like old world mafia style italian food, I would highly recommend Tufano's. Al Capone gave money to his personal cook before he was sent to Alcatraz to open a restaurant so that he could share his cooking with everyone and it is still run by the family of his cook. It is located in Little Italy. There is also a gangster tour, but I haven't done that yet. Have a great time!