National Mario Day is celebrated annually on March 10th honoring Mario from the popular Nintendo game. This is a gamer holiday that is celebrated on March 10th because of the way the date appears, when abbreviated (Mar.10), it looks just like the name Mario! According to nationaldaycalendar.com Mario, the Italian plumber, first appeared in Donkey Kong in 1981. In 1983 Mario got his own game with his brother Luigi. Mario is known as being the most famous video game character ever created. Over 210 million copies of the Mario game series have been sold.