Clemens Bimek invented a shut-off valve for the vas deferens, the tubes that bring sperm from the testicles out of a man's body. The Bimek SLV Spermatic Duct Valve is essentially a vasectomy with a gummy bear-sized on/off switch that you control from outside. So far, Bimek himself is the only person outfitted with the devices. He's currently seeking investment and medical approval for commercialization in his home country of Germany and beyond. From the company site:
(In 1998, while) watching a health advice program on TV, Clemens Bimek saw a segment about vasectomies, an operation he had never heard of before. He then asked himself: “Why not just insert a valve instead?” At the time he passed the patent office in Berlin-Kreuzberg everyday on his way to the construction site, where he worked. One day he decided to do some research on the topic and discovered that a few developments had already been attempted in this direction, but to him, these methods seemed overly complicated and therefore impractical. Bimek had, from that point, begun to further develop his ideas and to work on a first prototype…
(In 2008, after developing the idea and prototypes) Clemens Bimek attempted to convince different urologists to perform the valve implantation on him. A few were prepared to do this, but were stopped by the ethics committee at each clinic. He finally found a microsurgical specialist, who allowed him to observe 3 vasovasostomies. The specialist stated that he was prepared to implant the valve for Bimek’s self experiment and even obtained approval from the relevant ethics committee.
Bimek SLV Spermatic Duct Valve (via Mysterious Universe)