National Sleepy Head Day is observed on July 27, 2017. National Sleepy Head Day (Finnish: Unikeonpäivä) is celebrated in Finland every year. Traditionally on this day, the last person in the house to wake up is woken up using water, either by being thrown into a lake or the sea, or by having water thrown on them. It is based on the story of the Saints of Ephesus who slept in a cave for some 200 years during the Middle Ages whilst hiding from persecution by Decius, the Roman Emperor at the time.
In the city of Naantali, a Finnish celebrity is chosen every year to be thrown in the sea from the city's port at 7 a.m. The identity of the sleeper is kept secret until the event. People who are chosen have usually done something to the benefit of the city. Every city mayor has thus far been thrown to the sea at least once. The celebrations continue into the evening in Naantali and include activities for people of every age. (With material from: Wikipedia)