If you are a designer and you want to play YouTube video on your page background, Tubular is great option for you. It is a jQuery plugin that lets you set a YouTube video as your page background by using a single line of javascript code.
You need to call tubular on your BODY tag with the YouTube ID and your content container DIV as parameters
$('body').tubular('someYTid','wrapper');
where someYTid is the YouTube ID and wrapper is your containing DIV.
Enjoy It.