Desktopia is a customization concept for Mac OS X. Thanks to it’s very simple and unobtrusive interface you will be able to configure desktopia to automatically change your desktop picture based on a specified time of the day.
For example a beautiful sunrise at 7:00AM or a starry sky at 10:00PM. Just drag & drop the pictures that you have chosen on Desktopia’s window, set the time, and voilà! Like they say… “set it, and forget it!”