I've added some code to allow the embedding of youtube videos. This will probably be more useful and fun in the Happy Historian Lounge than in the public areas, but it's there in case you'd like to use it in a post.
The syntax is [youtube]URL[/youtube]. You should be able to just copy the URL from youtube and paste it inbetween the [youtube] opening and closing tags.
This seems a very good video to give as an example, (thanks very much to philebus at http://www.tarocchino.com for creating this excellent introduction to tarot).