The small routine above can be cut and pasted to the body section of your pages. It will produce 4 random colors and a 5th gif image background assuming you have a gif background named bg1.gif at the root level of your system.
Take out the un-needed type showing the background color and use this to dynamically improve any of your spml pages.
By adding a few lines including your pages graphic headers you can easily serve random headers using this same routine, or by the same token this same routine could be used to make up dynamic page footers.
Download the Dynaback Demo Archive