Festivus is an annual holiday created by writer Dan O'Keefe and introduced into popular culture by his son Daniel, a scriptwriter for the TV show Seinfeld. Although the original Festivus took place in February 1966 as a celebration of the elder O'Keefe's first date with his future wife, Deborah. Many people now celebrate the holiday on December 23, as depicted on the December 18th, 1997 Seinfeld episode. According to O'Keefe, the name Festivus just popped into his head.
The holiday includes novel practices such as the Airing of Grievances, in which each person tells everyone else all the ways they have disappointed him or her over the past year.
Then after the Festivus meal, the Feats of
Strength are performed, involving wrestling the head of the household to the floor, with the holiday ending only if the head of the household is actually pinned. Of course there are Festivus Miracles which are said to occur from time to time.
I ran across this children's drawing of a Festivus celebration. It's so cute that the kid's Mom is holding the Festivus pole.