I think the most fun (as a group) are colorectal surgeons. I have met a few who don't measure up, but the vast majority have an exceptional sense of humor.
As for off-color humor and just plain profanity laced tirades, I would have to go with Orthopods. I even remember a study in the British Medical Journal (BMJ) which had observers in an OR count the number of profanities from different types of surgeons, and I think Orthopods won hands down:
F Fausto Palazzo and Orlando J Warner
Surgeons swear when operating: fact or myth?
BMJ, Dec 1999; 319: 1611
Of course, this same issue had people having sex in an MRI machine, so I don't know about the review process. If you don't believe it:
Willibrord Weijmar Schultz, Pek van Andel, Ida Sabelis, and Eduard Mooyaart
Magnetic resonance imaging of male and female genitals during coitus and female sexual arousal
BMJ, Dec 1999; 319: 1596 - 1600