Eat
Let's be honest. The best thing about Michaelmas is the food.
As the story goes, when Michael threw Satan down to earth, he landed in a thorny blackberry patch. Satan cursed the fruit, stamping and spitting on it. As such, September 29 is considered the last day of the year for Christians to “safely” enjoy blackberries. It’s customary on this day to enjoy blackberry pastries and deserts, make blackberry jam, and make a goose glazed with blackberry. In fact, goose is culturally customary on Michaelmas and there are a plethora of stories about how that tradition came about (I won’t list them all here). If you can’t get a goose, a whole chicken or Cornish hens are appropriate as well.
If blackberry treats aren’t your jam (no pun intended!), make a Devil’s food cake and “slay” it with the serving knife (then let your children enjoy it with cocktail swords). Angel food cake and deviled eggs would also be on-theme.