This isn't in Chicago, but Evanston Art Center has animation type classes. It is located on Sheridan Rd in north Evanston. If you live on the north side of the city it might work for you. Check out the website.
Also, for summer you might look into I.D. Tech camps. This is a national outfit that hosts various technology-based summer programs, both day and overnight. In this area, I know they have sessions at Northwestern and Loyola and other places. My son who is 14 now has been doing that for several years. I know they have animation type stuff as well as a lot of film-making and digital photography, web design, animation, and lots of gaming design programs. This is BIG FUN!
Good Luck!