Hmmm…I was trying to reply to “Chronos” here…but I don’t think it will let me…
Mork’s appearance on Happy Days was NOT a backdoor pilot. It was intended as a one-off ep…but the ratings were so big that ABC was smart enough to immediately green-light a series about the Orkan alien. Mork and MIndy was a straight-up spinoff of HD.
Top of the Heap has been debated fiercely over the years…hard to believe that TV execs thought that would be a good idea for a back-door pilot… Some believe it was also simply a spin-off…
Mayberry R.F.D. is really the all-time hybrid BP/SO, isn’t it??? By all accounts, they added Ken Berry to the Andy Griffith cast with the intent of spinning them off into their own series…but it’s the same town…with many of the same characters…all in the same situation…more like an Archie Bunker’s Place or a Three’s A Crowd than a TRUE spinoff… Tomato, Tomahto…
One episode of Batman: The Animated Series (“Showdown”) is mostly a Jonah Hex Wild West story, framed by the device of the main story being recounted to Batman and Robin via a tape left behind by agents of Ra’s al Ghul.
I remember watching that episode of The Brady Bunch as a kid in the 1970s. I don’t think we knew what a “backdoor pilot” was back then, but it did seem an odd episode.
Seems like I’m in the minority, but I liked The Farm episode of The Office. It was supposed to be the pilot of the spinoff about Shrute farms, but NBC passed on it, so it was shown during the original series instead. Dwight’s brother and sister were certainly unique and both have had pretty good careers regardless; they seemed to have good rapport amongst themselves. “Who’s taking the farm?” Brother: “Not it.” Sister: “Not it.” Dwight: “It!”