Harry Potter and the Methods of Rationality

"Oh, really?" said Draco in the loudest drawl Harry had ever heard. "That sounds interesting. What sort of contest, Potter?"

Er...

"Contest" had been as far as Harry's inspiration had gotten. What sort of contest, he couldn't say "chess" because Draco wouldn't be able to accept without it looking strange, he couldn't say "arm-wrestling" because Mr. Goyle would crush him -

"How about this?" Harry said loudly. "Gregory Goyle and I stand apart from each other, and no one else is allowed to come near either of us. We don't use our wands and neither does anyone else. I don't move from where I'm standing, and neither does he. And if I can get my hands on Neville's Remembrall, then Gregory Goyle relinquishes all claim to that Remembrall he's holding and gives it to me."

There was another pause as people's looks of relief transmuted to confusion.

"Hah, Potter!" said Draco loudly. "I'd like to see you do that! Mr. Goyle accepts!"

"It's on!" said Harry.

"Potter, what?" whispered Draco, which he somehow did without moving his lips.

Harry didn't know how to answer without moving his.

People were putting their wands away, and Mr. Goyle swooped gracefully to the ground, looking rather confused. Some Hufflepuffs started over towards Mr. Goyle, but Harry shot them a desperately pleading look and they backed off.

Harry walked toward Mr. Goyle and stopped when he was a few paces away, far enough apart that they couldn't reach each other.

Slowly, deliberately, Harry sheathed his wand.

Everyone else backed away.

Harry swallowed. He knew in broad outline what he wanted to do, but it had to be done in such a way that no one understood what he'd done -

"All right," Harry said loudly. "And now..." He took a deep breath and raised one hand, fingers ready to snap. There were gasps from anyone who'd heard about the pies, which was practically everyone. "I call upon the insanity of Hogwarts! Happy happy boom boom swamp swamp swamp!" And Harry snapped his fingers.

A lot of people flinched.

And nothing happened.

Harry let the silence stretch on for a while, developing, until...

"Um," someone said. "Is that it?"

Harry looked at the boy who'd spoken. "Look in front of you. You see that patch of ground that looks barren, without any grass on it?"

"Um, yeah," said the boy, a Gryffindor (Dean something?).

"Dig it up."

Now Harry was getting a lot of strange looks.

"Er, why?" said Dean something.

"Just do it," said Terry Boot in a weary voice. "No point asking why, trust me on this one."

Dean something kneeled down and began to scoop away dirt.

After a minute or so, Dean stood up again. "There's nothing there," Dean said.

Huh. Harry had been planning to go back in time and bury a treasure map that would lead to another treasure map that would lead to Neville's Remembrall which he would put there after getting it back from Mr. Goyle...

Then Harry realised there was a much simpler way which didn't threaten the secret of Time-Turners quite as much.

"Thanks, Dean!" Harry said loudly. "Ernie, would you look around on the ground where Neville fell and see if you can find Neville's Remembrall?"

People looked even more confused.

"Just do it," said Terry Boot. "He'll keep trying until something works, and the scary thing is that -"

"Merlin!" gasped Ernie. He was holding up Neville's Remembrall. "It's here! Right where he fell!"

"What?" cried Mr. Goyle. He looked down and saw...

...that he was still holding Neville's Remembrall.

There was a rather long pause.

"Er," said Dean something, "that's not possible, is it?"

"It's a plot hole," said Harry. "I made myself weird enough to distract the universe for a moment and it forgot that Goyle had already picked up the Remembrall."

"No, wait, I mean, that's totally not possible -"

"Excuse me, are we all standing around here waiting to go flying on broomsticks? Yes we are. So shut up. Anyway, once I get my hands on Neville's Remembrall, the contest is over and Gregory Goyle has to relinquish all claim to the Remembrall he's holding and give it to me. Those were the terms, remember?" Harry stretched out a hand and beckoned Ernie. "Just roll it over here, since no one's supposed to get close to me, okay?"

"Hold on!" shouted a Slytherin - Blaise Zabini, Harry wasn't likely to forget that name. "How do we know that's Neville's Remembrall? You could've just dropped another Remembrall there -"

"The Slytherin is strong with this one," Harry said, smiling. "But you have my word that the one Ernie's holding is Neville's. No comment about the one Gregory Goyle's holding."

Zabini spun to Draco. "Malfoy! You're not just going to let him get away with that -"

"Shut up, you," rumbled Mr. Crabbe, standing behind Draco. "Mr. Malfoy doesn't need you to tell him what to do!"

Good minion.