As a native of chicago(wishing i was there now), ill give you a list of interesting things to do.
since youre in the loop, ill try and keep it focused around there
-michigan ave
-water tower place
-museum of science and industry
-shedd aquarium
-check out a bulls or blackhawks game at the united center
-navy pier(weather permitting)
-go to the top of the sears tower or john hancock
-bears game if theyre in town
-tour of wrigley field.
-watch second city
as for food and bars
-chicago deep dish pizza is a must( lou malnatis,uno's and due's are my favs)
-smoque bbq its on the north side though
-theres tons of bars in wrigleyville(murphys, the billygoat ect..)
-most resturants are fine
-buddy guys legends
I dont spend a lot of time in the loop. i like being on the north side more.
Chicago's the best city in the world if you make the most of it. have a good time there, theres a ton of things to do.