http://urbanelegends0.tripod.com/urbane_legends.htm

One myth that I hear of with increasing regularity these days can be traced back to the Italian province of Palermo. It starts with that much glorified and romanticized institution of Italian culture, The Mafia. Known locally as Cosa Nostra, the illegal actions of the Mafia have long been a thorn in the side of the justice officials in Palermo, and it is interesting to see how these diverse elements tie in to build the predominantly North American urban legend of Casu Marzu.
Part One: The Myth

As the story goes, there can be found in certain parts of Italy (Myth variants: Hungary, former Soviet Republic, Deep South of U.S.A) a particular delicacy, which though illegal, is highly sought after. In all variants of the myth, this 'delicacy' is known by the same monikers: jumping cheese, maggot cheese, Casu Marzu. The Myth would have some unsuspecting rube believe that a round of pecorino cheese that has been left to ferment and nurture fly-larvae is a delicacy known as Casu Marzu. This 'cheese' is said to be brown, with the consistency of a thick pudding or blanc-mange. It is used as a spread for bread or crackers, served with biscotti and wine, or alternately dissolved in vodka and grenadine for a decadently piquant liqueur.

Part Two: The Reality

This Urban Legend was started in the early years following the second world war, that much is known. What remains unclear is who was the first to propagate the myth.

The first school holds that it began as tales told by American soldiers returning home from the war.

The second school of thought presents it as a prank that was played by the locals on allied soldiers seeing Italy for the first time. The locals would present some spoiled cheese to them claiming it was a delicacy, and not wishing to offend their hosts, the visitors choked it down.

The third, and most likely school of thought is that Nadine is absolutely batshit-insane and has been making shit up for some time now.