Recently i got an assignment to make a fullscreen case display for a printing company. At first i looked at a flash solution. But since im not too fond of flash and we quite recently got support for javascript fullscreen in some browsers, i decided to make it with javascript instead.
And now for the good parts some code.
//webkit browsers element.webkitRequestFullScreen(); //firefox element.EnterFullScreen();
This will work for regular divs and iframes etc.
If you want fullscreen on a html5 video element the code is the same for firefox but differ for webkit browser. To get fullscreen on a video in a webkit browser. Just use video.webkitEnterFullScreen(); instead.
This was just a short start on the subject. To get things started on the blog. I will update it later on. If you want to read more i suggest you read this great article http://www.thecssninja.com/javascript/fullscreen.