Probably my first post in bad taste:
The Romans even had a special name for the middle finger -- they called it digitus infamis (infamous finger) or digitus impudicus (indecent finger).
Want to see some notorious examples: You might want to check this one. (The best one is the close scrutiny of O.J.Simpson's)
There's even a book: "The Finger: A Comprehensive Guide to Flipping Off". The above page even has a reason why you should buy it: If you buy only one book this year, you'd be an idiot to pass this one up. .