I prefer this one:
3 baseball fans are walking along some railroad tracks when they come across the naked torso of a murdered woman. The Sox fan says, "We gotta call the police, but let's give her her dignity first." So the Sox fan takes off his hat an puts it on top of her left breast. The Cardinals fan says, "Agreed," and removes his hat and puts it over her right breast. The Cub fan calls the police on his cellphone, gives the police the location of the body, and does what the other two baseball fans did, removes his hat, and places it over her vagina.
The cop shows up and says, "What do we have here?", and picks up the White Sox hat, looks under it, and places it back down. The cop then picks up the Cardinals hat, looks under it, and places it down. The cop then picks up the Cubs hat, looks under it, places it down, looks under it, places it down, looks under it once again, and places it down.....
At this point the Cubs fan screams, "What's the matter with you? Don't you have any sense of decency?" The cop stands up, looks at the Cub fan, and says, "Sir..... we have a problem here." The Cub fans says, "What's that?" The cop replies, "Usually when I look under a Cubs hat I see an asshole under it."