Bindweed Screensaver Manager is an innovative new screensaver manager and randomizer. Run it as as a screensaver, and it will detect your normal screensavers and run them at intervals you choose. (It can even run up to twenty at once, in small panels.) The intuitive 'Hearts' interface allows you to control not only which screensavers are chosen, but how often individual ones are likely to appear - it's not only more powerful than other screensaver randomisers, but also easier to use!
Other options include music or chimes, and the ability to run non-standard screensavers such as .exe files.