At the Daley Bicentennial Plaza, in the heart of Millennium Park, you can get in shape with yoga, aerobics and dance classes (all of which can be found in the recreational building). Come for ice skating in the winter (free admission and open from December 1-March 1) or roller skating in the summer. Don't worry if you don't have a pair of skates...they're available to rent for $6 a pair. Tennis, softball and day camp are other summer amenities to take advantage of.