Thinking about it for a minute, I think the difference between "hacking” and “munchkin-ing”, insofar as there is one, is that the former is about the kind of results (unusual/unobvious) and the latter is about the scale of results (large relative to effort).

Yeah, I kind of missed it. Hack is sort of something you do to something. Munchkinning is more... ontological. You are the munchkin if your existence is oriented to this sort of thing.

But I suppose if you use it as a verb, it could basically be a more transgressive version of hack.