Festivus is both a parody and a secular holiday celebrated on December 23 that serves as an alternative to participating in the pressures and commercialism of the Christmas season. It has been described as “the perfect secular theme for an all-inclusive December gathering”. This was introduced to the masses in a Seinfeld episode titled “The Strike”. From Wikipedia 

Air your grievances, exhibit fetes of strength and celebrate around the Festivus pole! Happy Festivus to you all good people.