It is the annual Bonus episode - because the people who appear on this show always say so much good stuff, it doesn’t all fit into their original episodes, so at the end of each year we get to enjoy all the extra bounty. Coming up, we’ve got a mythical disappearing island, geese, human dictionaries, the dubious history of the Body Mass Index, a Eurovision thing that has puzzled me for years, Victorian death department stores, and much more.