Jared linked me to a simple page that allows you to embed HD YouTube videos on any page.

By default, YouTube does not [currently] allow embedding of HD YouTube videos. If you wanted to see a particular video in HD, you had to go to the video’s YouTube page and hit “watch in HD”. But if you use this script provided at this webpage here, you can pass this rule and get HD video up and running on your own webpage.

Here’s the “Where the hell is Matt (2008)” video in HD.