http://vimeo.com/austinherring
This video on the green is very helpful in understanding what the green screen does and how it works. It is really well done and informative, also is slightly funny. He explains that the green screen is a worm hole capable to show anything. He says people have lied by saying that the green screen is keylight and removing certain hues. I enjoy the background music in the video. His examples he shows us in the video are cool and hilarious how they had a girl show up in the guys stomach.