Here is a really good encapsulated chunk near the beginning of chapter 6:
It has the setup for Harry's background, the basis for what makes this version of Harry different (science), a dramatic challenge, and finally promises of epicness and wry humor.
The Muggle world had a population of six billion and counting. If you were one in a million, there were twelve of you in New York and a thousand more in China. It was inevitable that the Muggle world would produce some eleven-year-olds who could do calculus - Harry knew he wasn't the only one. He'd met other prodigies in math competitions. In fact he'd been thoroughly trounced by competitors who probably spent literally all day practicing math problems and who'd never read a science-fiction book and who would burn out completely before puberty and never amount to anything in their future lives because they'd just practiced known techniques instead of learning to think creatively. (Harry was something of a sore loser.)
But... in the wizarding world...
Ten Muggle-raised children per year, who'd all ended their Muggle educations at the age of eleven? And McGonagall might be biased, but she had claimed that Hogwarts was the largest and most eminent wizarding school in the world... and it only educated up to the age of seventeen.
Professor McGonagall undoubtedly knew every last detail of how you went about turning into a cat. But she seemed to have literally never heard of the scientific method. To her it was just Muggle magic. And she didn't even seem curious about what secrets might be hiding behind the natural language understanding of the Retrieval Charm.
That left two possibilities, really.
Possibility one: Magic was so incredibly opaque, convoluted, and impenetrable, that even though wizards and witches had tried their best to understand, they'd made little or no progress and eventually given up; and Harry would do no better.
Or...
Harry cracked his knuckles in determination, but they only made a quiet sort of clicking sound, rather than echoing ominously off the walls of Diagon Alley.
Possibility two: He'd be taking over the world.
Definitely include this line:
"So now I've got to find some way to kill an immortal Dark Wizard," Harry said, and sighed in frustration. "I really wish you had told me that before I started shopping."
I think that this chunk of chapter 6 would be good (or extracts of it):
"All right then," Harry said. "Sounds pretty nicely wrapped up." He sighed, scrubbing his palm over his head. "Or maybe the Dark Lord didn't really die that night. Not completely. His spirit lingers, whispering to people in nightmares that bleed over into the waking world, searching for a way back into the living lands he swore to destroy, and now, in accordance with the ancient prophecy, he and I are locked in a deadly duel where the winner shall lose and the loser shall win -"
McGonagall's head swiveled, and her eyes darted around, searching the street for listeners.
"I'm joking, Professor McGonagall," Harry said with some annoyance. Jeebers, why did she always take everything so seriously -
A slow sinking sensation began to dawn in the pit of Harry's stomach.
McGonagall looked at Harry with a calm expression. A very, very calm expression. Then a smile was put on. "Of course you are, Mr. Potter."
Aw crap.
If Harry had needed to rationalize the wordless inference that had just flashed into his mind, it would have come out something like, "If I estimate the probability of McGonagall doing what I just saw as the result of carefully controlling herself, versus the probability distribution for all the things she would do naturally if I made a bad joke, then this behavior is significant evidence for her hiding something."
But what Harry actually thought was, Aw crap.
Harry turned his own head to scan the street. Nope, no one nearby. "He's not dead, is he," Harry sighed.
"Mr. Potter -"
"The Dark Lord is alive. Of course he's alive. It was an act of utter optimism for me to have even dreamed otherwise. I must have taken leave of my senses, I can't imagine what I was thinking. Just because someone said that his body was found burned to a crisp, I can't imagine why I would have thought he was dead. Clearly I have much left to learn about the art of proper pessimism."
"Mr. Potter -"
"At least tell me there's not really a prophecy..." But McGonagall was still giving him that bright, fixed smile. "Oh, you have got to be kidding me."
"Mr. Potter, you shouldn't go inventing things to worry about -"
"Are you actually going to tell me that? Imagine my reaction later, when I find out that there was something to worry about after all."
McGonagall's smile faltered.
Harry's shoulders slumped. "I have a whole world of magic to analyze. I do not have time for this."
N.B. I haven't listened to the podcast.
My favorite bits are when we learn about the physics of magic. Hints of how their universe must actually work
Also my main beef with the work is that we learn too little and too slowly of the answers to Harry's questions. (Such as "how do you think with a cat's brains".)
This was what confirmed Eliezer's skill as a writer in my mind. He resisted the (typical nerdish) impulse to vomit out pages of obsessively detailed explanations, instead leading the reader on with tantalising hints spaced far apart. It probably accounts for a lot of the book's notorious addictiveness.
The bit in Chapter 4 about taking advantage of the wizarding world's financial system was pretty fun too.
From the very end of Chapter 4:
"That's the spirit! And does a 'mokeskin pouch' do what I think it does?"
"It can't do as much as a trunk," McGonagall said reluctantly, "but a mokeskin pouch with a Retrieval Charm and Undetectable Extension Charm can hold a number of items until they are called forth by the one who emplaced them."
"Yes, I definitely need one of those too. It's like the super beltpack of ultimate awesomeness! Batman's utility belt of holding! Never mind a swiss army knife, you could just carry a whole tool set in there! Or other magic items! Or books! I could have the top three books I was reading on me at all times, and just pull one out anywhere! I'll never have to waste another minute of my life! What do you say, Professor McGonagall? It's in the best of all possible causes."
"Fine. You may add another ten Galleons."
Griphook was favoring Harry with a gaze of frank respect, possibly even outright admiration.
"And a little spending money, like you mentioned earlier. I think I can remember seeing one or two other things I might want to store in that pouch."
"Don't push it, Mr. Potter."
"But oh, Professor McGonagall, why rain on my parade? Surely this is a happy day, when I discover all things wizarding for the first time! Why act the part of the grumpy grownup when instead you could smile and remember your own innocent childhood, watching the look of delight upon my young face as I buy a few toys using an insignificant fraction of the wealth that I earned by defeating the most terrible wizard Britain has ever known, not that I'm accusing you of being ungrateful or anything, but still, what are a few toys compared to that?"
"You," McGonagall growled. There was a look on her face so fearsome and terrible that Harry squeaked and stepped back, knocking over a whole pile of gold coins with a great jingling noise and sprawling backward into a heap of money. Griphook sighed and put a palm over his face. "I would be doing a great service to wizarding Britain, Mr. Potter, and perhaps the entire world, if I locked you in this vault and left you here."
And they left without any more trouble.
Losing the 2-4-6 game in chapter 8. It was the first time I heard about cognitive biases. They sounded like a rather big deal and I wondered why nobody had ever bothered telling me about them. I started reading the Sequences, created an account and here I am.
When did you say "Ok, that's it, I gotta read all of this now"?
Chapter 7, when Harry starts experimenting with magic and testing the mokeskin pouch, planted the hook.
[ETA - I know that's out of bounds - but that's the first bit that grabbed me, honest.]
Yeah, this.
I think that when you choose the part to quote for the trailer, you should make sure to leave the viewer wanting more. The viewer should be thinking "what's next?" and then go looking for it.
"Bag of element 79," Harry said, and withdrew his hand, empty, from the mokeskin pouch.
Most people would have at least waited to get their wands first.
"Bag of okane," said Harry. The heavy bag of gold popped up into his hand.
Harry withdrew the bag, then plunged it again into the mokeskin pouch. He took out his hand, put it back in, and said, "Bag of tokens of economic exchange." That time his hand came out empty.
Harry Potter had gotten his hands on at least one magical item. Why wait?
"Professor McGonagall," Harry said to the bemused witch strolling beside him, "can you give me two words, one word for gold, and one word for something else that isn't money, in a language that I wouldn't know? But don't tell me which is which."
"Ahava and zahav," said McGonagall. "That's Hebrew, and the other word means love."
"Thank you, Professor. Bag of ahava." Empty.
"Bag of zahav." And it popped up into his hand.
"Zahav is gold?" Harry questioned, and McGonagall nodded.
Harry thought over his collected experimental data. It was only the most crude and preliminary sort of effort, but it was enough to support at least one conclusion:
"Aaaaaaarrrgh this doesn't make any sense!"
The witch beside him lifted a lofty eyebrow. "Problems, Mr. Potter?"
"I just falsified every single hypothesis I had! How can it know that 'bag of 115 Galleons' is okay but not 'bag of 90 plus 25 Galleons'? It can count but it can't add? It can understand nouns, but not noun phrases that mean the same thing? The person who made this probably didn't speak Japanese and I don't speak any Hebrew, so it's not using their knowledge, and it's not using my knowledge -" Harry waved a hand helplessly. "The rules seem sorta consistent but they don't mean anything! I'm not even going to ask how a pouch ends up with voice recognition and natural language understanding when the best Artificial Intelligence programmers can't get the fastest supercomputers to do it after thirty-five years of hard work," Harry gasped for breath, "but what is going on?"
"Magic," said Professor McGonagall. She shrugged.
"That's just a word! Even after you tell me that, I can't make any new predictions! It's exactly like saying 'phlogiston' or 'elan vital' or 'emergence' or 'complexity'!"
Professor McGonagall laughed aloud. "But it is magic, Mr. Potter."
Harry slumped over a little. "With respect, Professor McGonagall, I'm not quite sure you understand what I'm trying to do here."
Over the weekend the Methods of Rationality audio-book podcast tipped 1000 downloads, and I figured in celebration I'd put a trailer or two out on YouTube. Nothing fancy, just some stills/pics with an audio clip of 30-60 seconds. Thing is, I don't know what would work best for this. So I'm asking any readers of the fanfic - what first really captured your attention when you started reading Methods of Rationality? When did you say "Ok, that's it, I gotta read all of this now"? Or, if you're a listener to the podcast, are there any particular points that you thought were cool enough to share widely?
The restrictions are that it should be somewhere in the 30-60 second range, and that it has to be from the first 6 chapters (since that's all that's been recorded so far).
Thanks!