The CW Series The Flash and Arrow they began a new tradition amongst comic book TV shows celebrating Christmas. Although, other shows on CW have begun to embrace the holidays as part of their series at all started in the first and second seasons of Arrow.
At one time it was traditional on different comedy and drama series, that were not superhero based series, to have a holiday or Christmas themed episode. For example across the NCIS franchise on CBS network, there were Noel seasonal, episodes over the years and quite often the holiday was a background to the story or action happening within the framework of the show.
Over time that tradition seemed to die down on most network shows, however, Arrow has a background in family relationships, had episodes that again utilized the Christmas holiday as a background for the storyline on in the show. Whether the Christmas toasts during holiday parties or even decorating a large Christmas tree in the background this show reignited celebrating the Christmas holidays for TV.
Adding on to this tradition, The Flash has also begun to incorporate Christmas themes into episodes during the holiday season. In fact, this latest seasonal episode used a Christmas party to set up a chain of events which was left our hero Barry Allen, played by Grant Gustin, in a dire situation.
By embracing the holidays and use them as a background has even infused newer shows on the CW such as Legends of Tomorrow, which is on his third season, and Supergirl, the newcomer to the CW has been noticed with the Noel, as well.
As these shows are based on DC Comics characters, it should be no surprise to longtime comics fans to the fact that since the forties DC Comics has produced various holiday Christmas specials within their comic book universes. It is great to see the translation of an idea long-established in DC Comics make its way to the small screen.