You definitely know what a Charlie Card is, and you might even know a little about the folk song, "M.T.A.," that inspired the cards' name. But do you know all about the charged political environment surrounding the tune? Dissent magazine has a detailed article relating the history of everyman Charlie of the "M.T.A." song to Cold War politics in Boston. It's full of hard facts and fascinating trivia--did you know Charlie's original name was Angus?......