My best brainwashing story would have to come from the Southern Baptists. As a teenager I had been invited to a sleep-over event that was taking place on a Friday night at a local church. Or rather, my girlfriend had been invited, and wanted me to come along despite me being desperately irreligious. I went along to see what it was like.
All the kids were hanging out, playing games, having a pretty good time. They had a scavenger hunt scheduled which took us all over town. We came back and they had pizza delivered - cool deal. My girlfriend and I, not knowing our place, had wound up at the end of the line. With a bit of mysticism (`Jesus said "the first become last so shall the last become first"`) they put us at the head of the line - a kind gesture designed to win the affection of the new kids?
Everybody chows down on pizza and there is an unlimited amount of soda, candy, pixie stix and other sugary products to consume. Kids start getting wired in a huge way. We get to ~1am and the folks organizing invite everybody to a room on the 2nd floor for a movie.
As we come in, they shut and lock the doors behind us. Lights are turned down. Now you've got a huge room full of extremely wired kids, sitting in the dark, focused on the only source of entertainment around: the television.
They show us a Rapture movie.
The film opens up with a young, handsome man who loves Jesus with all his heart. He feels that today is the day of the Rapture, and he tells his family so. Lo, his family does not believe him and they scoff at this notion.
The only person who listens is his youngest brother - a 6 year old kid. He believes, too, and he loves his older brother very much.
They spend the film trying to convince friends and loved ones to repent and take Jesus into their hearts. After forty minutes of this, the young man and his kid brother go down to an airport to board the plane that takes them to heaven. (They needed to have some way to "go away", symbolic of the departure of the faithful during rapture.) Long, tearful scene where the family shows up and tells them not to go, but they reply they must because they love Jesus.
And the next day, rapture hits, people everywhere disappear, and the remaining family members acknowledge that they are damned, yea, verily. Much wailing and gnashing of teeth. Welcome to the end of days.
The lights come on and kids are crying their eyes out. No surprise; you take a bunch of kids hopped up on sugar and make them watch a film about the apocalypse, where half the main character's family winds up not going to Heaven - it's a perfect recipe.
And in this moment of sorrow and anguish, here come the elders, wanting to talk about how important Jesus is and why you need to take him into your heart. And why it's so important to make sure your brothers, sisters, parents, and grandparents all do too. After all, you don't want to wind up like that family in the movie, right?
Next came a question and answer session, where kids asked things like "will my family really go to hell if they don't all love jesus?". You can guess how this goes.
They wrapped up with a challenge/response ploy, with the organizers asking questions like "Who is the LORD?" and kids screaming back ``JESUS!`` "Who do you love with all your heart?" ``JESUS!``
The kids are generally left alone after that to talk amongst themselves and to unwind from the sugar high.
It's probably been ten years since this sleep-over thing, but I can still remember the details clearly. I can only imagine the impression it made on the others.