Back when there was no cable, just about every network show did a Christmas show either the week before or after Christmas. Many of them were quite forgettable, but 41 years later I still remember this one. In 1976 "One Day at a Time" did an episode that was basically a variety show, put on by the characters, for a retirement home.
I was a freshman in college at the time and I remember this one all these years later for just one number - Mackenzie Phillips and Valerie Bertinelli performing "Don't Go Breaking My Heart" dressed up as Elton John and Kiki Dee. That was one of the popular rock tunes of 1976. There are pieces of the episode on youtube including that number, which was done quite well.
The weird part about all of this is that Jerry Perenchio, Norman Lear's business partner, was partly responsible for bringing Elton John to the United States. Norman Lear was the creator and producer of One Day at a Time. Season one of this show is on DVD, but season two did not make it, so as far as I know there is no way to get a complete copy of the episode unless you know somebody with one of the earliest VCRs who taped it and retains a working copy.
If you get a chance to see it, it is definitely a blast from the past.