I recently read Flowers for Algernon, a very powerful, involving little 1966 book. From Wikipedia:

The story centers on Charlie Gordon, a mentally retarded janitor who volunteers to take part in an experimental intelligence-enhancing treatment. His progress parallels that of Algernon, a laboratory mouse who had been "enhanced" earlier. The story is told from Charlie's point of view and written as a journal, in progress reports (or progris riport as he initially spells it), which he keeps as part of the experiment. Succeeding entries trace Charlie's ever-increasing comprehension and intelligence in the aftermath of the treatment, as he passes through "normalcy", and then reaches super-genius level, becoming vastly more intelligent than the doctors who invented the procedure (he learns 20 languages, reads books at one page per second, writes a piano concerto, and disproves the hypothesis of the experiment that he was the subject of, among other accomplishments).

I've been sitting here today thinking, gosh - I think I go through a similar, but more compact, swing on the Algernon scale myself. Which is to say, I never accidentally learn twenty languages, but I can often look at code I've written the day before and think, 'oooh shit, that's just a bunch of letters and numbers... wtf???' There is one factor, one magic elixir that can turn the seemingly random string of coloured text back into a shining machine of organic perfection: coffee. Its mildy alarming how true this is. I think I'm going to have to get used to the notion of self-medication, for without coffee, I am nothing. Nothing, I tell you.