Back in the early 1900s, Fritz von Opel, grandson of Opel founder Adam Opel, was enamored with rocket propulsion. As the company's director of testing and the man in charge publicity, Opel had quite an outlet to fulfill his rocket-powered fantasies. Hence, the 1928 Opel Motoclub you see above.
The example showcased so beautifully here doesn't happen to have rockets attached to it, but a number of Motoclubs apparently did, as seen on the right. The 500cc single-cylinder engine could reportedly push the silver-and-red Opel motorcycle up to about 75 miles per hour, after which a foot pedal lit the rockets, sending the bike to a calculated top speed of 132 mph.
Sadly (or perhaps fortunately?), the German government forbade Opel from conducting a world-record top speed attempt, fearing that such a run on two wheels couldn't possibly be safe. The good news, though, is that decent examples of the Opel Motoclub can still be found from time to time, minus the six solid-fuel rockets, of course. Sounds like a good DIY weekend project, no?
[Source: Bike EXIF]