It's the one where Rhys ponders which gift to buy for Gwen. I put the titles of many Christmas songs into the text, so it is also a riddle, see if you can find them all! It just occured to me that I never uploaded the German version to my LJ, you will have to wait for next Christmas for that to happen now.
And here is the story in our newspaper. They even put a nice matching pic in it! I am hiding it behind the LJ cut: