Alessandro from 5Volt.eu has made this real simple and cool clock . The Laser Sundial Clock Project uses a Atmel microcontroller to move a servo with a line laser connected to it. The result is a single line that can simply represent the time on the wall.
"This is a simple project of a sundial wherein the pinion is replaced by a line LASER I took from a LASER level. The LASER is mounted on a RC servo which in turn is driven by a micro controller. The micro controller keeps the time and turns the RC servo accordingly."