ActiveEarth

ActiveEarth is a world time clock with a gorgeous day and night merge of NASA's Visible Earth satellite images in flat maps or a globe. It has accurate time zone data for more than 500 cities and you can add your own. Your PC's clock can be synchronized to atomic time. AE has several, scalable analog clock styles. You can even track important future events with countdown clocks. A screensaver shows your favorite clocks and map from the main program.

Limitations:

30-day trial