I was reading the September 2009 issue of Scientific American Magazine. It was a special issue on origins. One of the smaller articles was on the origins of the vibrator ... it was invented around 140 years ago, and when electricity came to common use, the vibrator because a household appliance before the iron did. Obviously it must have been invented for some non-sexual use and then someone found out the happy misuse accidentally, right? Wrong! It was invented to make doctors more money.
It turns out there was a common ailment at the time called hysteria that affected women only. The treatment for this disease was for a medical doctor to, by hand, rub the (ahem) "pelvic" area of the affected female until the patient underwent (ahem) "hysterical paroxysm". That's right, your great grandmother went to the doctor to get a little something something. No wonder she wanted your mother to marry a physician. This procedure was time consuming, however, and it was found that what sometimes took the physicians hours to do by hand, could be done in a few minutes by use of the aforementioned mechanical device. Doctors could see more patients and deliver more effective treatments.
The Scientific American article is not online, however Wikipedia has an entry on the disease. Ah the good old days, when the air was clean, you could get a soft drink made with cocaine, and your doctor gave you personal service.
Makes you wonder what people will think of our society in another 125 years.