Of course, if you don't like cartoons and that isn't depressing enough for you, how about this one, called 'Threads':
http://www.youtube.com/watch?v=eT96sgTwmvo
Don't expect a happy ending though...
I like the British sense of hopeless doom. Makes it obvious how we won the War of Independence.
Frankly, I'm surprised the Brits didn't just mass suicide.