Yup, the ol' monkey-at-a-typewriter theory that it'd eventually produce a Shakespearian sonnet.
Not gonna happen of course, if you think it through. There's also zero chance that a monkey at a keyboard would eventually cough up a Mozart masterpiece.
Reason why in both these cases is that, rather than being anywhere-near-random, the "plunking" tends to centralise around a few keys, not even taking into account the rhythmic chaos in the case of the music example.