In this video, check out a homemade Geochron world clock created by Justin Shaw.

The Geochron Web site explains:

[A] Geochron allows any observer to determine what time it is anywhere in the world. Physically the Geochron looks like a framed world map, about 2×3 ft. in size. The colorful map itself is an endless belt that is driven slowly from left to right by an electric clock motor in synchronism with the rotation of the earth.

But, in this instance, it is not the map that moves. This timepiece uses programmed LED lights imposed over a map of the world to simulate night and day in different regions. The clock is even programmed to account for seasonal light patterns!

via Hack A Day

Instructions how to make this gadget at Instructables