Harry Potter and the Methods of Rationality

"Innervate!" said the young voice of Susan Bones, and Hermione's eyes flew open and her lips drew in air with a gasp, her lungs feeling heavy like there was a huge weight resting on her chest. Beside her, Hannah was already sitting up, holding her head in her hands and grimacing. Daphne had warned them that this would be a 'hard' fight, creating a certain trepidation in Hermione, and indeed in all of them. Except maybe Susan, who'd just shown up at the appointed meeting-time, and walked alongside them without speaking, and fought the seventh-year bully until she was the last girl standing. Maybe the Gryffindor had been reluctant to fight the last daughter of Bones, or maybe Susan had just gotten very lucky; at any rate, when Hermione had tried to sit up again, she'd realized that her chest had felt heavy because there was, in fact, a rather large body sprawled on top of her.

And you wouldn't want to forget about magic either, even if the actual moment of casting a spell only formed a very small part of your day. It was the whole point of Hogwarts, after all.

"Okay, how about if we all ride around on skateboards?" said Lavender. "We could get places faster than walking. And we'd look really awesome on skateboards, Muggle artifacts may not be as fast as broomsticks but they look cooler - we should vote on it -"

As for the remaining fractions of time, you would fill that according to your nature: gossip about upper-year romances, or books and study sessions.

Hermione reached out a trembling hand to grasp her copy of Hogwarts: A History from where it had fallen, the ever-comforting book only a pace distant from where she herself had ended up on the floor, after the red-robed upper-year girl had "bumped" her into a wall. And then the older Gryffindor witch had walked away without a look back, only a whispered "Salazar's -" and a word that hurt her more than anything the Slytherins said about mudbloods, 'mudblood' was just a strange wizarding word but Hermione knew the word the Gryffindor had said. She couldn't get used to it, she just couldn't get used to being hated. It still hurt just as much every time it happened, and somehow it hurt even more coming from the Gryffindors who were supposed to be the good ones.

Harry had divided up eight of his soldiers among the other armies, as ordered; he'd voluntarily given up two Chaotic Lieutenants, sending Dean Thomas to Dragon Army and then trading Seamus Finnigan to her for Blaise Zabini, who Harry had said was being "underutilized" in Sunshine. Lavender had elected to join most of SPHEW in Sunshine; Tracey had decided to stay with Chaos.