I saw this over on Patrick’s Mokuren Dojo blog (visit it, it’s a great blog):
According to the post in question, this is an aikido technique called a gedanate. Not having studied aikido before (though I’ve read Twigger’s rather ace Angry White Pajamas, which is an ace little book), I don’t know much about this kind of stuff, but I know that the complete lack of visible effort used to send the guy flying off to the side is awesome. Check out Patrick’s original post for more links and discussion on the topic.
Personally, I think it just looks cool 🙂