The Chicago Blues Festival is the largest free blues festival in the world and remains the largest of Chicago's Music Festivals. During three days on five stages, more than 500,000 blues fans prove that Chicago is the "Blues Capital of the World." Past performers include Bonnie Raitt, Ray Charles, B.B. King, the late Bo Diddley, Buddy Guy and the late Koko Taylor.
Its happening right now at the Millenium Park in Downtown Chicago. Check out the line up and more here: http://www.cityofchicago.org/city/en/depts/dca/supp_info/chicago_blues_festival.html