I have heard a story that the CIA ordered a 55 gallon drum of LSD, by mistake, as part of a wider, earlier "what do psychedelics do?" research program. Then they had this stuff and everybody got to "play" with it; there was supposedly a period when LSD in the coffee was an office hazard there. Then it gradually leaked out a little further and helped spark more general interest and more manufacturing and the love children.
The appealing part of this story was the bit where Sandoz called them back and asked "did you want enough of this to light up the country?" and some ignorant bureaucrat said "that's whats on the form, ship it already." That fits my cynicism about government operations, especially unsupervised ones.
The stories about the government involvement in cocaine are less funny.