I'm just busting your balls - enjoy Chicago. Last time I was there I did the Wrigley Tour (it was after the baseball season), Boat Tour and a Bears game (for $250 a ticket). I didn't have to pay for the hotel, but with the flight and some quality dinner + a night out at Second City I'm sure I spent $1,000.
If you have time - the Second City was experience was awesome. Highly recommended, as is the architectural boat tour.