...on the last episode of Battlestar Galactica ("Guess What's Coming to Dinner?" is the ep title). The song is called "Gaeta's Lament".
Commentary and video can be found here: Battlestar Galactica's Latest Song is full of Clues.
However, I would have to agree with the commenter on that site that the blog post title is misleading. The blogger, Meredith Woerner, doesn't exactly untangle the lyrics and give us a new interpretation. (Also, Meredith breaks up with Gaeta in this blog post. Which if fine. Gaeta can be MY boyfriend if she doesn't want him.)
It's a start, anyway.