Solar System Clock is a digital clock widget that also shows an animation of the planets in the solar system rotating around the sun (also known as an orrery).
You can tweak the speed of the animation and the viewing angle, and you even get to decide whether or not Pluto is a real planet.
Install the Opera widget here: http://widgets.opera.com/ja/widget/5620/
(C) Per Johan Groland 2006