On "Seinfeld," Frank Costanza’s alternate holiday for Christmas is Festivus.
Festivus is introduced in the Season 9 episode "The Strike," which first aired on December 18, 1997. Frank presents it as a non-commercial alternative to the stress and consumerism associated with Christmas, declaring it a celebration "for the rest of us."
The sitcom’s version features an undecorated aluminum pole, a Festivus dinner, the airing of grievances, and feats of strength. The holiday is generally observed on December 23 within the show’s mythology, although that date and several traditions were created or formalized for television.
Festivus was not invented entirely by the Seinfeld writers. Writer Dan O’Keefe adapted it from a private family tradition created by his father, Daniel O’Keefe. The real family observance differed substantially from Frank’s television version, so it is a mistake to treat Festivus as an ancient or conventional religious holiday.