Monty Python and the Holy Grail was made on such a small budget that some of the castles were made out of cardboard!
Monty Python and the Holy Grail was the first "proper" movie made the comedy group called Monty Python. Made during 1975, The Holy Grail was different from their previous work in that it consisted of more than just various skits, but was an entire movie. The movie parodies the legend of King Arthur and his attempt to find the Holy Grail.
The film was made with a budget of only $365,274, an incredibly small sum for a modern movie, yet it went on to gross nearly $130 million! The film was so successful it has become a sort of cult classic, resulting in a 2005 Tony Award-winning musical Spamalot.
To save money the film was shot almost entirely in the same castle with different lighting and angles to appear to be different buildings. In fact, producers were so strapped for cash that they decided to forgo the use of actual horses and just included the characters banging coconuts together to mimic the sound! That later became one of the most iconic gags in the movie. It's amazing what lack of money can do for ingenuity and comedy.