Not exactly a "joke", but amusing nonetheless:
What's Your Pirate Name?
I came up with:
Black Davy Vane Like anyone confronted with the harshness of robbery on the high seas, you can be pessimistic at times. You tend to blend into the background occaisionally, but that's okay, because it's much easier to sneak up on people and disembowel them that way. Arr!
Suits me well. LOL