Every year on July 27th, Finland celebrates “National Sleepy Head Day” — a tradition that dates back to the Middle Ages and which can be something of a rude awakening for Finns who sleep late. According to custom, the last person still asleep in a household will be awakened, picked up, and thrown into a lake. The tradition is based on the idea that anyone who slept late on Sleepy Head Day would be lazy and unproductive for the rest of the year. The earliest official record of the tradition is from a religious text of 1652, but the celebration goes back further. In days gone by, crowds would gather in carnival mood for the official day, proceeding house to house to hunt down unlucky residents who were still enjoying their sleep and subjecting them to a good soaking.