A small screensaver that shows a minimal web page.
See typesaver.net for more info.
Configure the URL-s with OS X standard user defaults/preferences system.
defaults write net.typesaver.saver url http://example.com/
defaults write net.typesaver.saver previewUrl http://example.com/#preview
The default values are http://typesaver.net/#screensaver for typical use, and http://typesaver.net/#screensaverpreview for the preview in System Preferences.