I remember about twenty years ago some teenagers were caught fornicating in one of the additional schools. The schools were downstairs, essentially separated from the rest of the KH. They weren't just happened upon, though. I think they told some other teen that this is that they were going to do and that teen dropped a dime on them. The girl involved was the niece of the congregation's pioneer leading sister.
More recently, about three years ago, two sisters got into a fight because one was cheating with the other's husband. It was a real fight, too. Doors were broken off of the hinges at the literature counter. Hair flying everywhere. They were all over the place.
I recall also when a young brother was disfellowshipped, as it was being read from the platform, his sister fainted out and fell out on the floor in a pretty noisy fashion. It held up the meeting as EMS had to be called.
Lastly was the angry brother that was in the process of being disfellowshipped. He was going with an elder's daughter. The brother was 24 and the daughter was 13. One night, during the TMS, he barged into the KH screaming and yelling about how they (him and the 13 year old) could not be busted up. (He was eventually disfellowshipped, reinstated, and is now bucking for ministerial servant.)
Those were the ones that were most memorable. Of course I can think of many more