Downtown on the el is a long ride. If you don't want to go all the way downtown there are a bunch of restaurants very near the Damen-O'Hare stop of the el. This is the Wicker Park neighborhood. I was at a meeting at the Ohare Hilton a few weeks ago and took the el to the Blue Line Bar and Grille.
http://www.bluelineloungeandgrill.com/ Pretty good food, and quite reasonably priced.