Keith Richards as Jack Sparrow's dad? It seems to have a bit to do with the fact that Johnny Depp drew his primary inspiration for Jack Sparrow from Richards. So it was only natural that Richards would appear as the father of the character himself.
Spiritual Licensee: The films have a great deal in common with the seafaring horror stories of William Hope Hodgson, especially "The Ghost Pirates" and "The Derelict".
Throw It In: Jack's "bring me that horizon" at the end of Black Pearl was ab-libbed by Johnny Depp.
When Barbossa tells Jack "we named the monkey Jack", Jack the Monkey cocks his head and grins. This was pure coincidence.
In On Stranger Tides, while Jack runs in the jungle, he trips and falls - and Johnny Depp made sure to keep into character, by hitting the hole with a sword once he got up again!
Word of Saint Paul: Johnny Depp has said that Jack Sparrow has syphilis.