A human corpse into poofing into existence from nowhere wouldn't be in itself a bad outcome.

Free food! (It doesn't count as cannibalism if the corpse has never been a member of your species!)

I am reminded of a game we played in elementary school:

There are 100 pieces of candy in a jar, and 20 students. Each student gets to vote "share" or "selfish". If EVERYONE votes to share, the candy is split evenly. If ONE person votes "selfish", they get all the candy. If MORE than one person votes "selfish", no one gets candy, and the experiment is repeated until either the candy is distributed, or X iterations (3-5 seems normal) have passed.

Before each iteration, the students are allowed to discuss strategy. The solution, of course, is for a single trustworthy person to make a binding commitment to vote "selfish" and then evenly distribute the candy. By pre-commiting to vote "selfish", everyone else knows that voting "selfish" themselves will result in no candy - unlike a commitment to have everybody share.

I've always considered it a decent test of group rationality and social skills whether or not this consensus actually gets reached before the final iteration. I've seen groups that hit on this, had a single iteration with a few outliers testing it just to be sure that the person would really vote "selfish" like they said, and then implementing the strategy. I've seen others where 10-20% of the audience simply would not believe the person who made the pre-commitment, and so there was never a successful iteration

I think I'd make a decision other than "try that new restaurant on the outskirts of town" for the evening before the world ends. If I don't know the world is going to end, then my decision now mightn't be optimal in light of that additional information (maybe that still tests something interesting, but it isn't quite the same thing).

In a group, with a leader who knows the exercise:

Get a volunteer to act as a judge (or a few to act as a jury, in a large group). Have her leave the room. The leader presents the rest with a short set of Contrived Hypothetical Situations, each with finite options and either clearly-defined outcomes for each option, or a probabilistic distribution of outcomes for each option. The leader says, "Please write down your choice for each problem, sign your paper, and turn it in to me. Then I'll call in the judge, and have her decide on each problem. You get a point wherever her decision agrees with yours. The winner is the one with the most points." When the judge is called in, however, the leader doesn't tell them the actual problems. Rather, the leader just reports the outcomes (or distributions), and asks them to choose which outcome or distribution is best. The winners are announced based on that.

Example: One of the situations given is some variant of the trolley problem. When the judge comes in, she is just asked whether she'd prefer one person to get hit by a trolley, or five. Everybody laughs as she replies "...one?"

Example: The problem given to the group is "You drive 45 minutes away from home to go to a new restaurant for dinner. When you get there, you discover that you dislike the ambience and the selection is poor. You remember that you have decent leftovers at home. You're mildly hungry. Do you try the restaurant anyway (25-minute wait, 10% very enjoyable meal, 10% decent meal, 80% unenjoyable meal) or just head back home (5-minute-prep once you get home, 100% chance decent meal)?" The problem given to the judge is "You're mildly hungry. In 25 minutes, you can have a meal that is (10% very enjoyable, 10% decent, 80% unenjoyable). Or, in 50 minutes, you can have a guaranteed decent meal."

I think you should go with Vaniver's idea. (Edit: Vaniver now has multiple ideas up. I mean the one about giving orders to malicious idiots. Completely off-topic: that's also a useful way to explain tasks to people with Asperger's Syndrome or other neurological oddities that cause executive dysfunction.)

I also think this reminds me of something (fiction) writers talk about a lot: they've hit on the way people won't sympathize with "a billion people died/starved/were tortured/experienced dust specks in their eyes" but will sympathize with "Alice was mobbed by dust specks and blinded" and will sympathize even better if you give some specific details about how it felt. And then they go on to talk about how to make Alice someone the reader cares about and how to craft sentences and other stuff that's relevant to them but irrelevant here.

But maybe something like making up a character and talking someone through xyr experience using the product step by step, in the kind of detail a novelist would use to describe the climactic fight scene.

Another idea that occurred to me is some sort of exercise where two people would pair up. One would have to do a novel task or navigate some kind of obstacle course blindfolded and the other would have to give directions. They wouldn't be able to get away with "turn right at the statue" but would instead have to give directions like "turn right at the big smooth stone thing" and... I guess if you were doing something like that, you'd want to give the non-blindfolded partner a picture or map and NOT let them see the one doing the actual task. Otherwise they'd just be able to say "okay, turn right now... turn left... turn left again..." and that would defeat the purpose.

Do people typically say "life isn't fair" about situations that people could choose to change?

Look at the reference for the Szalinski paper. I'll bet it has a really small circulation...

I should have remembered what day it was...

A matter with the Comed-Tea that was bugging me for a while:

Chapter 14:

SO THAT'S HOW THE COMED-TEA WORKS! Of course! The spell doesn't force funny events to happen, it just makes you feel an impulse to drink right before funny things are going to happen anyway!

Hypotheses: Comed-Tea on person = impulse to drink, Comed-Tea not on person = no impulse to drink.

According to Chapter 12:

Harry couldn't help but feel the urge to drink another Comed-Tea. (And when he didn't...) Harry inhaled his own saliva and went into a coughing fit just as all eyes turned toward him.

So no matter what, even if you don't end up drinking it, you will get the Impulse before something funny happens.

Chapter 46:

I have been saving them for special occasions; there is a minor enchantment on them to ensure they are drunk at the right time. This is the last of my supply, but I do not think there will ever come a finer occasion.

So Harry has used up all of his Comed-Tea. (edit: it appears that Harry actually has tons left unless he's not mentioning some he drank/gave away, look at bottom of post)

...

WHY? WHYYY?!

It is apparent that you'll still get the impulse to drink whether or not you do end up drinking. So why didn't he save a can he's never ever going to drink?

Even if Harry will end up choking on his saliva, wouldn't the early notification of something ridiculous happening be helpful to him in any way? Like... it'd be an early warning to be prepared for whatever another person could say/do in conversation. Or if he's looking for interesting information, say from the library, he can just walk by all the shelves until he gets the Impulse-- that'd be an indicator that he's near the shelf that has the interesting book. There might be more uses.

Chapter 14:

Thankfully, Harry’s panicking brain remembered at this point that he did have something he’d been planning to discuss with Professor McGonagall. Something important and well worth her time. It was at this point that Harry realized he was faced with a priceless and possibly irreplaceable opportunity to offer Professor McGonagall a Comed-Tea and he couldn’t believe he was seriously thinking that and it would be fine the soda would vanish after a few seconds and he told that part of himself to shut up.

The charm even works for other people. If, for example, Harry wishes to test whether or not someone knows that Voldemort is alive, he could see if he has the Impulse to give that person a drink, all while thinking about saying that "The Dark Lord is still alive". If he gets the Impulse, they don't know. If he doesn't, then they already know/has been suspecting that he's been alive.

Chapter 8:

The boy reached into his pouch and said, "can of soda", retrieving a bright green cylinder. He held it out to her and said, "Can I offer you something to drink?"

Hermione politely accepted the soda. In fact she was feeling sort of thirsty by now.

In fact, just asking, "Are you feeling thirsty?" seems to be enough to trigger the charm's apparent spit-taking powers. Harry could think about talking about Voldemort, and ask if the other person's thirsty. If yes, they would take whatever he's going to say as a surprise, if no, then they won't. Geebus this thing is powerful.

edit: actually, I'm going to check the text and see Harry actually used up his supply. Be right back.

Chapter 7: “Two dozen cans please.” (24) He tossed a can to Draco and then started feeding his pouch... (23) (Harry's drinking one too) (22) Harry snarled, threw the can violently into a nearby garbage can, and talked back over to the vendor. “One copy of The Quibbler, please.” He paid over four more Knuts, retrieved another can of Comed-Tea from his pouch... (21)

Chapter 8: The boy reached into his pouch and said, “can of soda”, retrieving a bright green cylinder. He held it out to her and said, “Can I offer you something to drink?” (20)

Chapter 12: Harry reached into his pouch and whispered, “Comed-Tea”. (19)

Chapter 46: “Three sodas." (16)

Nevermind, Harry lied, he still has tons unless he's been drinking them and not mentioning it. However the Comed-Tea hasn't been mentioned since, so it might actually be all gone.

I wish to register my alarm at this:

This was actually intended as a dry run for a later, serious “Solve this or the story ends sadly” puzzle

Given that he was "amazed" at our performance this time, presumably an equivalent performance would pass the future test — but even if that's true it doesn't comfort me much.

I humbly beg our author to consider simply withholding updates, rather than issuing an ultimatum that may result in us never getting the "true" ending. "I won't post any more chapters until you solve this," rather than "I'm going to torch the last few years of your life if you're not smart enough."