At an orientation event in the first week of my freshman year of college, they had some guy come and play music by sliding his moistened fingers over glasses he had arranged on a table in front of him and tuned with a turkey baster. It was mesmerizing. I watched him for like a half hour, and somewhere in there all the guys I thought I might become friends with realized I was weird and ditched me to go check out what else there was to see.
Anyway, it turns out ol’ Ben Franklin saw a similar performance in England in the middle of the 18th century, but instead of just standing there guffawing like a goon, he went home and built an instrument that improved upon the same premise. He called it the armonica, and it became popular in Europe both for its music and its purported medicinal benefits. Among others, Franz Mesmer, who gave his name to a verb I used in the second sentence of this blog post, played the armonica.
You can read much more about the fascinating story of Franklin and the armonica at Out of This Century, which came via Josh R. And you can learn why the armonica fell out of favor. In short: It makes you crazy!