May Day 
is an ancient northern hemisphere spring festival and usually a public holiday;[1] it is also a traditional spring holiday in many cultures. Dances, singing, and cake are usually part of the celebrations that the day includes.
In the late 19th century, May Day was chosen as the date for International Workers' Day by the Socialists and Communists of the Second International to commemorate the Haymarket affair in Chicago. International Workers' Day may also be referred to as "May Day", but it is a different celebration from the traditional May Day.
https://en.wikipedia.org/wiki/May_Day
Lei Day 
The most common festivities on Lei Day are hula, lei making demonstrations and contests, and the crowning of the Lei Queen and her court. What better way to celebrate Lei Day than by booking a trip to one of Hawaii’s many resorts!
https://www.daysoftheyear.com/days/lei-day/
New Homeowner's Day 
New Home Owners Day is also a great time to reflect on how far you’ve come on your home-buying journey, and how far you can still go. You could look back on completed household projects or draw up some plans for new improvements. You might find that just re-arranging your current furniture can completely alter the look of your home!
https://www.daysoftheyear.com/days/new-home-owners-day/
School Principals' Day 
Though the job title varies between countries (‘School Principal’ is used in North America, while ‘Head Teacher’ is preferred in the UK, for example) every school has to have a boss. Schools are like small businesses, with hundreds of customers (students) and dozens of staff (teachers, receptionists, cleaners and so on) and making it all run smoothly is the job of the Principal. It’s especially difficult if the kids are trouble-makers or the parents aren’t happy. Principals have varying responsibilities, from teacher evaluations to dealing with serious discipline issues, but at its heart their job is about providing the best environment for kids to learn.
https://www.daysoftheyear.com/days/school-principals-day/
http://www.famousbirthdays.com/may1.html