“Goel and Dolan (2001) finally found the orbitofrontal cortex (BA 10/11) to be associated with the appreciation of humour in the form of semantic and phonological jokes of the kind ‘Why did the golfer wear two sets of pants?… He got a hole in one,’ which are based on the juxtaposition of expectation and its resolution.”
from an interesting article by Ivar Hagendoorn