Dang. Where did I put that? Jason asked me to chime in on a discussion someone's having somewhere on the Michaelmas skip. Oh well, I'll just skip it. (wait for groans)
According to the Gottesdienst calendar (is there any other?), this year the skip is made to the Nineteenth Sunday after Trinity on September 30th. That is, we skip Trinity 17 and 18. This will line things up so that you arrive at Trinity 27 on schedule, November 25, before launching into Advent.
Why? you ask.
I'm afraid I misplaced that information as well, but I can do some recollecting and surmising. I'm guessing maybe this is British, perhaps having something to do with Cromwell. They observe "St. John's Tide," "St. Laurence Tide," etc. These are divisions of the Trinity season. When it gets to Michaelmas (Sept. 29), or the Sunday nearest, not only do we move to "Michaelmas Tide," we also shift to counting from the end of the Trinity season, setting our gaze already on latter days, at least to a degree. This becomes more pronounced in the last three Sundays of the church-year. I suspect that the heavy emphasis then on the Last Day is partly due to a very old, though not universal, custom of having a seven-Sunday Advent season.
Maybe somebody else has more information, but that's what I have. For now, anyhow.