In the film The Aristocrats (Penn & Teller?), they show Gilbert Gottfried telling 9/11 jokes two weeks after it happened. They had a Friars Club roast of Hugh Hefner at the time, in New York City, and they almost cancelled, but went on with it because, well, people needed a break from the gloom by then. So Gilbert Gottfried (he's the voice of the Aflac duck in tv commercials, by the way) begins his shtick by saying something like, "I had a little trouble getting hereÉ all the flights from LA had a stopover at the Empire State Building." Nervous, tentative chuckles, and someone in the back yells, "Too soon!", meaning too soon after the World Trade Center to tell jokes, but Gottfried pretends it meant he had delivered the punch line too quickly, so he tells the joke over again slowly. Gets a good laugh this time, so throwing what little restraint to the wind, he tells a long, detailed version of the title joke, "The Aristocrats", an extremely dirty joke shall we say, and people are laughing uncontrollably at his nerve and how they'll have to "clean it up a little for family television", "Ya think?!", and asking someone if missed a part, should he repeat it slowly?; they're laughing so hard they're "rolling on the floor, coughing up blood".

OK, here's a YouTube clip of the Aristocrats joke at the Roast. With Spanish subtitles to help you.
[Definitely over the top, vulgar language, be advised.]
http://www.youtube.com/watch?v=dnbHGmd8XNE&feature=related
or another excerpt of GG from the film, a more philosophical exegesis of the joke,
http://www.youtube.com/watch?v=hD1dc74QMPM