Acting in the Dark: The kids who sang in the "Every Sperm is Sacred" sketch later said they had no idea what they were singing about.
Banned in China: The film was originally banned by the Irish film censor in 1983 but subsequently widely available in Ireland on PAL UK TV videocassette since 1983 & later on DVD to this day (legally & uncut).
Cast the Expert: Graham Chapman plays a doctor in the "birth" segment, and is called "Doctor" in the Zulu War segment. He was a real-life doctor, with a medical degree from Emmanuel College, but he never practiced medicine professionally.
Enforced Method Acting: The infamous Mr. Creosote scene was filmed in a warehouse with no air conditioning and a dairy-based prop vomit that went bad after several days of shooting. This, combined with the content of the sketch itself, made the extras very nauseous and several of them (including one in the bottom right-hand corner) can be seen actually vomiting as they exit the restaurant covered in Creosote's remains.
Hollywood Accounting: Eric Idle, on his Exploits Monty Python concert tour at the Turn of the Millennium, noted that this movie was the only Python film made with major studio backing (Universal Pictures)...and thus the only one that apparently didn't turn a profit. So in this tour's version of "The Crimson Permanent Assurance", there's an additional verse about studio accountants.
Technology Marches On: The "Birth" sketch was, at the time, a cutting satire on what was seen as unnecessary spending on medical equipment. Nowadays, anyone who's seen a modern medical drama, with the surgeons surrounded by massive banks of electronic equipment, may wonder what all the fuss is about — to the point that operating without such equipment nowadays would be seen as unusual and dangerous. Other parts of the sketch though remain relevant.
Also, Cleese and Chapman tell the woman after the birth that she can get a video of the birth of her child on VHS and Betamax!
... and Super 8mm film!
Throw It In!: The line, "Hey, I didn't eat the mousse!" was an ad lib.
Uncredited Role: Nigel Hawthorne makes a small cameo in "The Crimson Permanent Aussurance" bit as the man walking by the building when the anchors are raised.
The second verse of "The Galaxy Song" was meant to be an animated sequence along with the instrumental part, but Terry Gilliam opted out of animating it in favor of shooting more of "The Crimson Permanent Assurance".
Before the Pythons decided to make a sketch movie about the meaning of life, two ideas were considered for the movie. The first was Monty Python's World War III, with sponsored armies and soldiers wearing military uniforms full of advertisements. Another idea was the Pythons being tried for fraud, accused of making a tax dodge, not a movie. They spend the entire movie trying to prove that they're shooting an adaptation of Hamlet in the Caribbean. At the end, they're found guilty and sentenced to execution, and each one of them gets to decide how they're going to die. The idea was used in the death sketch, where Arthur Jarrett has chosen to die while pursued by naked girls.
Two involving Mr. Creosote.
The sketch almost didn't make it into the film. Terry Jones' first write-up of the sketch with Michael Palin fell flat and had to be re-written by Graham Chapman and John Cleese (who saved the sketch from being binned because he wanted to play the head waiter, whom he thought had the funniest part).
Jones initially wanted Gilliam to play Mr. Creosote. Gilliam persuaded Jones to play the character instead.
The Crimson Permanent Assurance was intended as an animated sequence in the feature, for placement at the end of Part V. Gilliam convinced the others to allow him to produce and direct it as a live action piece instead.