I've had the need for a random-thingy that could output random images, random quotes and the like.
Therefore, I've created a small plugin called randomize - you can find it at http://linux.linux.dk/projects/randomize/
I use it on a few sites, fx. for changing the banner-image on blogs, to give a dynamic-effect and for fetching random quotes.
Anyway, the code is crap and the site above is slow - but if you can use the plugin for anything, please go ahead...