Word Clock is a typographic clock and interactive art work. Time is shown by highlighting appropriate words from one of over 30 languages. Select either the linear or dynamic rotary version, or periodically transition between both.
Note that this is an application and will appear in your dock rather than your system preferences. If you want to use it as a screen saver, you can set it into start at login and appear after a set time. It will then hide in the background.