This is going up a bit early, just because people are already talking about it and new folks are asking questions. @Chaos says the old thread isn't good enough and tasked me with making a new one, probably because I opened my big mouth at just the wrong time. So lo, the explanation comes: in just a bare few weeks, an annual phenomenon of confusion will bear down upon us like a shower of angry Tribbles.* Every year, as the days grow short and the weather grows cold, we creep slowly towards t