Strange fictional holidays

Whacking Day - May 10th, when one beats snakes to death with a club - The Simpsons

Shoe Giving Day - you exchange gifts of shoes - Hyperdrive

Dogbert Day - a holiday designed to replace all holidays-and be incredibly bothersome while doing so - Dilbert

Robanuka - robot day of leisure including dance and Jewish-style music - Futurama

Scotchtoberfest - version of Oktoberfest created by Skinner - The Simpsons

Soul Cake Days - a cross between Hallowe'en with trickle-treating and sticky toffee rat on a stick, and Easter, when wizards roll boiled eggs down the Tump and the Soul Cake Tueday Duck lays chocolate eggs - Discworld

Everybody Hide the Corn Day, Hay Day, the Day of the Princess Pig, and the Day of the Wheat - Rose Nylund reminisces on St. Olaf holidays - The Golden Girls

Garlic Tuesday - a day to celebrate all that is smelly - The Legend of Dick and Dom

Do Nothing Day - Nobita uses one of Doraemon's magical gadgets to declare Do Nothing Day - Doraemon

Beethoven's birthday observance - Schroeder creation, celebrated December 16th - Peanuts

Feast of Maximum Occupancy - Homer's creation, based on a sign at Moes - The Simpsons

Kwanaza - Futurama

Clam Day - Family Guy

Hogswatch - New Years and Christmas combined - Discworld

Flying Car Parts Day - Marvel Mash Up

Festivus - including a customary “Airing of Grievances” followed by a “Feats of Strength”. Festivus only ends when the head of the household has been wrestled and pinned to the floor - Seinfeld

Verdukian Holiday Of Mouth Pleasures - 30 Rock