There is a deck of playing cards scattered around the area. This one was in the grass in front of the apartment building next to mine (20th street), I saw them in the bushes in front of the Dental School and the Blood Center, in the planters in front of Humphry Hall on 17th street, and there was a Jack in front of the Library on 15th street. I believe I can see one on the front lawn of the house that is across the other street (Michigan Ave) from my apartment.
That house by the way, is not an unofficial Frat House like I originally thought. It is the Men's Rugby House, where senior members of the club team live. Which explains why there is so much beer.