Walking around the world:
"Since walking the lakefront bike path to work downtown every day for the past 11 years, I have covered the distance from Chicago to my hometown of Madrid, Spain, and back."

For fun:
Catching up with performances at the Chicago Symphony Orchestra, Steppenwolf Theatre, Court Theatre, Chicago Shakespeare Theater, Lyric Opera, Links Hall, Remy Bumppo Theatre, Writers' Theatre, and Chicago Opera Theater. "With seniors riding free on the CTA and Metra, my mom and I more often enjoy the ride into the Loop, where we attend the Sunday piano series at CSO—possibly the best piano program in the country."

If you have two hours in Hyde Park:
Walk around the neighborhood, perhaps stopping at the Oriental Institute Museum and then visiting the Seminary Co-op Bookstore "to complete the immersion in the humanities."

If you have two days in Hyde Park:
Day 1: Swim in Lake Michigan, have lunch in Hyde Park, walk around Kenwood, and take the CTA for dinner and music at Millennium Park.
Day 2: Take an early bike ride on the lake and visit Osaka Garden, visit O'Gara's bookstore, have lunch on the rooftop patio of the Medici, stop in 57th Street Books, and attend Court Theatre.