In its first season, The Brady Bunch had a Christmas episode, “The Voice of Christmas,” which aired on Dec. 19, 1969, on ABC.

Original cast members Robert Reed, Florence Henderson, Barry Williams, Maureen McCormick, Christopher Knight, Mike Lookinland ...

But in Season 2, producers went to the next level when they cast the real-life children of two of the main stars—as well as the daughter of the show’s creator. The episode was “The Slumber Caper,” and ...