National Gorilla Suit Day, which mysteriously falls on January 31 of each year, is perhaps the important holiday of the year. Every National Gorilla Suit Day, people of all shapes and colors around the world get their gorilla suits out of the closet, put them on and go door-to-door.
That's really all there is to it. You don't have to buy gifts. You don't have to fast, although some Orthodox Gorilla Suiters do. If you want to have a parade, fine. Just make sure all the marchers are wearing gorilla suits and that all the balloons are giant, inflatable gorillas.
– Mark Evanier