9-11.
I live in NYC. On 9-11-2001 I could look out at the horizon from where I was living and see the billowing smoke of the twin towers in the distant air. As I'm sure most of you remember, there was alot of uncertainty/ misinformation going around about just how serious the attacks were. People weren't sure if there were going to be more attacks, etc. for a few hours after the towers were struck. And of course most of us were stuck transfixed to our TV's for hours, not believing the devastation we were seeing (my family was fortunate to not have anyone hurt in the attack).
My witness family immediately went into religious overdrive. A few speculated that the "big A" might be starting, most at least thought there was some real significance to the terror attacks. If you remember, attendance numbers did spike a little in the US after this. If you have an even keener memory you'll remember that prior to 9-11 the Society had arrainged for some special meetings to take place around the country just after 9-11, meetings that originally were restricted to certain invited congregations to attend (of which my old congregation was one). Not suprisingly, when these meetings did occur (around 9-20, IIRC) way more people showed up than was originally planned for. My family arrived at Nassau Coliseum and had to stay in the car and listen to the program on the radio broadcast because all the seats were full in the building. (we had threads on this site about the event when it happened back then if you wish to do some kind of search)
Never at any point during the events did I fall into a JW mindset. I did not see the events as the beginning of "the big A", or a "sign of the last days" or as an indication that I should stop the then insipient stages of my fade out the organization. I saw the event for what it was; an unfortunate act of terrorism perpetrated by vile and delusional people in the name of a combination of blind religious fanaticism and a warped sense of political grieviance.
Literally, at some point late in the day of 9-11, it really hit me that I was definitely mentally out of the religion, almost certain to never return. My heart was with the families of the people who had lost loved ones (and at the time the few people still thought to be potentially alive in the rubble), I felt saddness for them, not worry about Armageddon. I felt anger at bin Laden, not Satan. I went to bed that night knowing for absolute certainty that the religion had zero control over me (up to that point I was only 95% sure ).
(If you remember, the special meeting turned out to be a total dud. IIRC, the highlight was some sort of useless JW resolution when everyone was expecting something "deep".)