Geek shows? (is that what they were called? or is that a made-up thing for current day renaissance faires?)
I would not want to see Monty Python-esque humor in this game. I think it would be completely incongruous with the rest of the material.
Personally, the humor I enjoy in these types of games usually comes in off-hand remarks from “people-in-the-street” - short, subtle things that just kind of make you chuckle. For KCD, that would be perfect so long as the “joke” doesn’t reference something contemporary or is otherwise a joke that relies on our modern knowledge of a past time (though, actually, that might still work).
From my understanding of the period (which, I fully admit, is miniscule) humor tended to be (as @Helena mentioned above) crude, or among the more refined folks it was more about being witty to an almost obscure extreme.
Anyway, great topic. I think there’s always room for humor in almost any game, including this one, but as others have said it has to be done right, especially in a game that aims to be so authentic.