I haven’t tried this on too many sites yet but it works on mine and a few others I tested out.
Append the following to one of your favorite websites that runs PHP:
?=PHPE9568F36-D428-11d2-A769-00AA001ACF42
So if you wanted to check out what it does on this site (which runs PHP) then you would go to the following URL:
http://www.billrini.com/?=PHPE9568F36-D428-11d2-A769-00AA001ACF42
I’ve seen a few different results based on which site I typed it in but the same result comes up no matter how many times you reload it in your browser. It might be based on what version of PHP the site is running but I haven’t been interested enough to research it any further than that.
Have fun.