If you are looking for a free screensavers manager and randomizer have a look at ScreenSaver Commander.

Nevertheless, this problem is easily solved. The ScreenSaver Commander will fill lacks of standard Windows screensaver option. Using this software you will be able to manage your screensavers, and run them in which-ever order you wish. So, you can enjoy not only one screen-saver, but all collection!

The program gives you much more functions to control screensavers than the standard Control Panel applet allows. You will be able to change time-out in hours and seconds, prevent starting a screen-saver if specified applications running, minimize all windows and so on.