Look at this miniature 16-Cylinder Gas Powered Stirling Engine
This would make the coolest desk accessory!
Wonderful video shows reverse jet engine thrust up close and in slow-motion
I've been flying a lot lately and one of the things I've taken notice of is the insane sound of the engines doing reverse thrust upon landing. Reverse thrust, in a very simple explanation, is when the engine opens up in such a way where the air being pushed through it is reverse in order to help slow an aircraft down. The split in the engines you see in the video above is this action taking place.
Here's one more marvelous one shown on an Airbus A380.