I've actually written about that on Programmers: http://programmers.stackexchange.com/a/235992/55400. The term was coined before Python Labs joined Zope Corp though (IIRC).

From http://en.wikipedia.org/wiki/Monkey_patch (references to footnotes are from original site):

The term monkey patch seems to have come from an earlier term, guerrilla patch, which referred to changing code sneakily – and possibly incompatibly with other such patches – at runtime.[2] The word guerrilla, homophonous with gorilla (or nearly so), became monkey, possibly to make the patch sound less intimidating.[2] An alternative etymology is that it refers to “monkeying about” with the code (messing with it).