May Day, which can be celebrated in any number of ways. It's a traditional pagan holiday, for one thing, routinely spent dancing around Maypoles, leaving flowers on a loved one's doorstep (if the recipient catches you at it, you are chased down and made to kiss them), crowning the Queen of the May, and other forms of springtime revelry. In the United States, today is also known as Law Day, on which we commemorate the rule of law. But for many folks around the world, May 1 is International Workers' Day (a national holiday in more than eighty countries), with many places combining the day's "Green Root" (pagan) and "Red Root" (labor) activities. I have a coworker who consistently takes it off from work, but most Americans seem oblivious to this international holiday. Try not to ignore our typo of the day, which was found 44 times in OhioLINK and 796 times in WorldCat.
(Workers Party poster, Donegall Street, Belfast, Northern Ireland, July 2010, from Wikimedia Commons.)