Many out of country visitors to usa are enjoying "blue man group" which is nonverbal performance-art type of show. pretty funny. blue man group plays in chicago and new york and perhaps boston too. 

The air show, now in its 40th year, runs usually the third weekend in august saturday and repeated in its entirety on sunday along the lakefront featuring mostly modern aircraft (ie: all the latest fighters and bombers) and helicopters. show runs from 11am to 4pm and best thing to do is to take a seat along the beach promenade somewhere between the northern part of center city and the lincoln park area. the best part is at 3:15 when the blue angels or some equivalent group fly their f-18's over the city for half an hour. they flew in between the buildings!!!  the city cleared out all the air space. i watched that part from my cousin's 20th floor apartment and those planes were crossing about 150 feet in front of our window at eye level. it was very very cool and i can't believe they allow this kind of stuff. this year they started a saturday evening show at sunset for half an hour with fireworks at navy pier. 

A nice activity is to take the boat tour for 1 1/2 hours which goes along the river through center city and shows you the architecture of the city's buildings. lots of things you wouldn't otherwise notice and chicago is famous for good architecture. if you go to the frank lloyd wright house (a good 20 minute drive out of center city), beware that it is a popular attraction and sells out; you can't go inside except on a tour. but you can walk around the neighborhood and see about 15 other houses, temples and a post office he designed.