I missed a major feast day.

Well, it's not very major, or even very known anymore. Thanks to the
Old Farmer's Almanac (oh how I love their information-packed site!),
now I know a little bit more about thisparticular custom, and where the phrase
"Godspeed" comes from.

January 12, 2009
Plough Monday

The first Monday after Epiphany (January 6) was the day for the
menfolk to return to work after the holidays -- although no work was
actually done on this day. Dressed in clean white smocks decorated
with ribbons, the men dragged a plow (plough) through the village and
collected money for the "plow light" that was kept burning in the
church all year. Often men from several farms joined together to pull
the plow through all their villages. They sang and danced their way
from village to village to the accompaniment of music. In the evening,
each farmer provided a Plough Monday supper for his workers, with
plentiful beef and ale for all.

Where does the saying "I wish you Godspeed" come from?

This dates back to a 15th century song sung by English ploughmen on
Plough Monday, the first Monday after Twelfth Day, the end of the
Christmas holidays. Before farm laborers went back to the fields, they
dressed all in white and went from door to door drawing a plough and
soliciting "plough money" to spend on a last celebration. The song
lyric "Godspeed the plough" expressed a wish for success and
prosperity and was soon shortened to just "Godspeed".

I've always used the phrase "red-letter day" to refer to a good or
enjoyable day; now I'll need to revise that usage:

The term "red-letter day" originates with the tradition of marking
holy days in a church calendar in red. We use the term here to
designate days of special significance in each month -- holidays,
astronomical happenings, anniversaries of historic events, and days
with memorable folklore attached.

I was aware of the special day of Epiphany this year, but wasn't quite
sure what it all meant. After a little digging around, I was able to
inform myself, having had no knowledge of such things in my
non-liturgical background. I feel I've missed out on a lot of history
there, and for me that's a loss. (Missing out on mathematical
knowledge, now that's a blessing.)

More to come here as the light is shined into my brain on special
days, seasonal events, and other things liturgy-related. Fascinating
for me, and if dull for you then consider it a non-medical sleep aid.
My Epiphany gift to you. It's not plentiful beef and ale for all, however...