In order to show the video ads, you need to select certain ad formats of image ads. Namely: 1. Medium Rectangle (300 X 250) 2. Large Rectangle (336 X 280) 3. Square (250 X 250) 4. Small Square (200 X 200) Please refer: http://dagsensecodes.com/2006/12/make-your-site-more-dynamic-use-video.html
I saw it from a site. But I forgot. I think the Google Video Ad was the AniBoom's campaign ad. It looks OK.