Stirling Engines, way cool desk toy + more!

 I was reading Slashdot this afternoon and I stumbled across this gem. Of course, being a gear head, I was curious how an engine might run without fuel. The principle is the known as the Stirling Engine, an external combustion engine that uses any constant external heat source to power it. Imagine the environmental impact of basically free rotational energy! On the companies website, they have a model that runs on the heat from your hand (the MM7) including a video of it (and other models) in action. How cool is that! You too can get your hands on one for about $380 from the American Stirling Company.