Fuck is a very interesting documentary, attempting to describe the word’s origins and follow the evolution of how the word is used. It’s a very old word, first appearing in print in the 15th century, but suspected of being much older.
The most amusing myth about the word, which i have never heard but is apparently quite common, is that the origin is an acronym for Fornication Under Consent of the King. How amusing. But it is shown to be clearly just a myth.
Lots of interesting things about the evolution of the common usage of the word, as well as how it is used in music, tv, movies and politics. Highly recommended.