I came across this site last night, and thought it was really funny. Apparently this guy was unemployed for a long time, and became frustrated with the lack of response his resume was getting, so he started writing ridiculous cover letters to get attention:

Hire Me Dumbass! Prank Letters

I particularly liked the snapple one, the pepsi one and the sea world one.

Update: Amazon has a bunch of the pages of this book online here.