kwam
Irishfan
Don't forget the Taste, the Museum of Science and Industry (superior to the Field Museum, IMHO), Ravinia Festival (if you're up for a drive, the Evanston people are lucky they're so close), or the Lincoln Park/Brookfield Zoos. The House of Blues always has something going on, too.
I went to the House of Blues an it was cool, but I really enjoyed the Blue Chicago, I thought it was a more "for locals" kind of place.
If Blues / Jazz are your thing - you have great options:
1) Buddy Guy's Legends - has a touristy reputation sometimes, but head down there on a Monday night. You will not be disappointed
2) Green Dolphin St. Great food and jazz.
3) Green Mill - Mondays, Wednesday and Saturdays (Tuesdays if you like swing). Chicago's jazz staple.
4) Checkerboard Lounge - In my opinion, it still is The place for Blues in Chicago - even after the move to Hyde Park. It was a needed move as at the old location's neighborhood was extremely seedy...
As Irish said - ravinia is great. The metra will drop you off at it from downtown...