1975’s “When Things Were Rotten” is a mashup of Mel Brooks’ screwball comedy with the classic tropes of Robin Hood on television, with mad schemes, colorful characters, and more than a hint of camp! The series was cut short after only 13 episodes after dwindling ratings – despite the critical praise, it was shifted around the schedules and never found a solid following.
That description is too kind. The first episode was kinda-sorta OK as juvenile humor goes (below), and the theme song was hilarious (further below), but the concept was too limiting to sustain a long run. They ran out of material and kept repeating gags that were lame to begin with.
The theme song:
Once upon a time, when things were rotten
Not just food but also kings were rotten
Soon the band of Merry Men begotten
They wore outfits made of plain-grade cotton
Helping victims was their business
Boy oh boy, was business good
Good for Robin Hood!
They laughed, they loved
They fought, they drank
They jumped a lot of fences!
They robbed the rich
Gave to the poor
Except what they kept for expenses!
So, when other legends are forgotten
We’ll remember back when things were rotten
Yay for robbin’ Robin Hood!

There were two TV shows in the mid-1970’s that were so bad they lived on in jokes for several years: “Supertrain”, which was about a super train, I guess, and “Hello, Larry”, which starred MacLean Stevenson from the MASH TV series. I think his character hosted a radio call-in show. Both flopped really hard. I think there were jokes about them in the early seasons of SNL. I never saw either of them, so IDK what their vices or virtues were.
Another show was always a punch line and usually made the “worst of all time” lists: Cop Rock.