For those who don't, here's the story. There's a song called "The MTA Song" that was written in 1948 about a man named Charlie who couldn't get out of the Boston subway system because he didn't have the nickel in exit fare that he needed. The song became a hit in 1959 when The Kingston Trio recorded it. I learned the song somewhere along the line, probably at summer camp, despite growing up in New York, not Massachusetts.
I can still recite the chorus of the popular song that I knew as "Charlie and the MTA":
Did he ever return? No, he never returned, and his fate is still unlearned. He may ride forever 'neath the streets of Boston, he's the man who never returned.
You can listen to a clip of this song here or here.
CharlieCards, indeed.