What Is Festivus, and How Do You Celebrate the Seinfeld Holiday? Share December 17, 2021 Dm4r Technology For some, the most important holiday in December falls on the 23rd. That’s the day to celebrate Festivus, the made-up holiday from an episode of Seinfeld, which has since taken on a life of its own. Read This Article on How-To Geek › Source : What Is Festivus, and How Do You Celebrate the Seinfeld Holiday?