Dreamt up in 2001 and first launched in 2004, a gentlemen Heiko Schmalz from Leipzig has created yet another testament to exquisite German engineering. In this case, a steam powered folding kayak. The steam boiler, hanging from the cockpit combing, is heated with wood and provides 0.3 horsepower to two side wheeler paddles. (picture after break)
It takes about half an hour to get the fire going and build the pressure up in the boiler, but after that, this fine vessel cruises comfortably at 4-5 km/h (~ 2.5 knots). Since its a kayak (a Pouch RZ85), you can steer with your feet while feeding the fire, watching the boiler pressure, and minding the water level. If you visit the original page [translation via google] you can see more pictures, and a small animation of the pistons turning.
Last year, Heiko was also featured on a German TV show, Simply Brilliant, that documents inventors and inventions. They report that Heiko has built steam engines in the past. Also visible are some ongoing improvements, including a nice red paint job on the paddle wheels. He is apparently looking to continue upgrading the system until is able to achieve hull speed for the kayak, about 8 km/hr.