The writer of Seinfeld, Dan O'Keefe, celebrated "Festivus" with his family growing up. It was a new holiday tradition that his father made up after reading about a Festivus holiday in a book. It was a crazy, silly holiday with unique traditions that later became a Seinfeld episode.
Today, Festivus is actually celebrated by hundreds of thousands. It has grown into a non-denominational fun holiday. Some stay true to the Seinfeld episode and carry out their actual traditions, others just do bits and parts. For most, I believe it's just a silly, crazy,fun way to celebrate the season. So, Happy Festivus to all!!