The song at the end

Maybe someone else has thought this too, I don't know, but the song they use at the end of this show sounds like a song I should know - a "real" song, so to speak, as opposed to just a closing theme. When I heard it the first time, I was like, "I know that song! What is that song?!" Anyone else ever thought that? Like maybe they reworked the lyrics for the purposes of this show or something...