I discovered this - although don't ask me how (or more accurately from where) as frankly I can't remember but I didn't actually come up with it myself. It's a special magical, mystical erm, thingy that when used with Firefox or Chrome creates a sort of ball game thing out of whatever web page you happen to be on.

First things first, switch off IE and Safari - it just won't work if you're on either of those.
Sorry, try again. 

Now, fire up Firefox and copy and paste the following into the Javascript console
(Go to: Tools/Web Developer/Web Console)

javascript:var i,s,ss = ['http://kathack.com/js/kh.js','http://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js'];for(i=0;i!=ss.length;i++){s=document.createElement('script');s.src=ss[i];document.body.appendChild(s);}void(0);

Right click and drag to manoeuvre the ball around and enjoy the exceptional sound track.
Clever eh.