Bring out yer dead .. Monty Python and the Holy Grail Trivia
Funds earned by Pink Floyd's album "The Dark Side of the Moon" went towards funding The Holy Grail. The band were such fans of the show they would halt recording sessions just to watch Monty Python's Flying Circus (1969).
The famous depiction of galloping horses by using coconut shells (a traditional radio-show sound effect) came about from the purely practical reason that the production simply couldn't afford real horses.
During one of the first screenings of the film in front of a live audience, director Terry Jones noticed that when music was played during the jokes, there was a marked reduction of laughter from the audience. He went back and edited the music out whenever a punchline was delivered. At subsequent screenings he noticed a dramatic increase in the audiences' positive reactions to the jokes. From that point on, whenever he directed, he remembered to stop the music for the funny parts.
During the witch hunt, Eric Idle bares his teeth and bites down on the blade of the scythe he is holding. This was not scripted; Idle was actually about to burst out laughing and bit his scythe to stifle himself so as not to spoil the take. (If you look closely, you can see him shaking slightly, trying to keep his laughing under control.) Michael Palin can be seen hiding laughter at the same time as well, while earlier in the scene John Cleese quickly turns his head to one side just before the shot cuts, though not quickly enough to hide that he has broken character and is grinning broadly. All three comment on each others' corpsing on the DVD commentary.
Since the armour the Knights wore was really made of wool, and the weather conditions in Scotland and England being what they normally are, the actors spent most of the shooting days being very cold and wet. To make matters worse, the hotel where they were staying only had a limited number of baths and hot water. At the end of shooting each day, there was a mad dash to see who could get back to the hotel first, and into some hot water. The Monty Python troupe all seem to agree that they did not enjoy much of the filming experience for this movie.
The airspeed velocity of an unladen swallow is roughly 11 meters per second, or 24 miles per hour, beating its wings 7-9 times per second rather than 43. It's true: a 5 ounce bird cannot carry a one pound coconut, but furthermore, no swallow weighs 5 ounces. The barn swallow, which is what most English people mean when they say "swallow", weighs only 20 grams (2/3 of an ounce).
In the Killer Rabbit scene, a real white rabbit was used. He was dyed with what was assumed to be a washable red coloring liquid in the shots after the battle. When filming wrapped the rabbit's owner was dismayed to learn the dye could not be rinsed off. Terry Gilliam described in an audio commentary that the owner of the rabbit was present and shooting was abruptly halted while the cast desperately attempted to clean the rabbit before the owner found out, an unsuccessful attempt. He also stated that he thought that, had they been more experienced in film-making, the crew would have just purchased a rabbit instead. Otherwise the rabbit himself was unharmed. The rabbit-bite effects were done via special puppetry by both Terry Gilliam and SFX technician John Horton.
The Black Knight was first played by John Cleese, but when Arthur cuts off the first leg a real one-legged actor (a local silversmith) was used. On the DVD Terry Gilliam reveals that a marionette was used to film the shot of the second leg being cut off, he also jokes that using the one-legged silversmith for the shot of the knight with no legs saved work, since they only had to dig a hole for one leg (Cleese has said that it was himself standing in the hole).
King Arthur: I am your king.
Woman: Well, I didn't vote for you.
King Arthur: You don't vote for kings.
Woman: Well how'd you become king then?
[Angelic music plays... ]
King Arthur: The Lady of the Lake, her arm clad in the purest shimmering samite held aloft Excalibur from the bosom of the water, signifying by divine providence that I, Arthur, was to carry Excalibur. THAT is why I am your king.
Dennis: [interrupting] Listen, strange women lyin' in ponds distributin' swords is no basis for a system of government. Supreme executive power derives from a mandate from the masses, not from some farcical aquatic ceremony.