The Stirling engine, invented by Robert Stirling in 1816, is a heat engine that operates by compression and expansion of gas. You may not have space for a giant engine at home, but this Böhm Stirling Engine Kit lets you build a desktop-size twin engine yourself. It has stainless steel screws and parts while the wheels and cylinders are made of polished solid brass.
According to the manufacturer, it will take about 3 hours to assemble the engine. The HB26 Twin Bridge Engine runs for up to 20 minutes. The above video shows it in action.