Couple of years ago on a Malev Hungarian 767 flight out of JFK to Budapest. The plane was not too full, but toward the back were three rather burly guys sitting next to each other in the 3-seat middle section. The guy in the middle was a slight bit rowdy (I thought he was drunk), and got progressively louder as the flight progressed. Finally, after some outburst, many of the passengers turned around, one of the guys in the aisle stood up and flashed some sort of badge of identification and they restrained the guy with those plastic tie things.

Not the most pleasant of flights, but nothing extraordinary besides some loud (and somewhat incomprehensible) noise.