The website probably uses Flash video, which is not supported by the iPad.
If you read this thread, there are some recommendations of apps that can convert Flash content into a form that's playable on the iPad. http://www.ipadforums.net/ipad-help/54705-flash-ipad.html
If you go to Giants.com from a mobile device, you end up on their mobile site and videos play without a problem on your device. I just tried it with my iPhone.