The idea to sell screensavers for Netscape Navigator hit me one night when I was fooling with a starfield applet. I realized that you could use the client pull feature introduced by Netscape with a long timeout to pull an applet which acted as a screensaver. As far as I know, it isn't yet possible to disable the Navigator's buttons from a Java applet, but who knows! They said flying toasters would never fly.
Anyway, here's how, for those who are curious. Just include the following line in your HTML markup, just before the title, inside the <head> container:
<meta http-equiv="Refresh" content="300;
url=http://www.hesketh.com/schampeo/projects/Faces/FaceSaver.html">
This page is set to go to screensaver in five minutes, like above (the units are given in seconds.) For more information on the nifty HTML trick used to pull the screensaver page, see Netscape's pages.