Harry Potter and the Chamber of Secrets

They found Percy, deeply immersed in a small and deeply boring book called Prefects Who Gained Power.
"A study of Hogwarts prefects and their later careers," Ron read aloud off the back cover. "That sounds fascinating..."

"All we've got to worry about now are airplanes." [Flying in the Ford Anglia]

"Can you believe our luck?" said Ron miserably. "Of all the trees we could've hit, we had to get one that hits back."

"You could've fried an egg on your face," said Ron. "You'd better hope Creevey doesn't meet Ginny, or they'll be starting a Harry Potter fan club."

"Careful not to walk through anyone." [At Nearly Headless Nick's deathday party]

"We weren't hungry," said Ron loudly as his stomach gave a huge rumble.

"Hearing voices no one else can hear isn't a good sign, even in the wizarding world."

"They'll catch the maniac who did it and have him out of here in no time. I just hope he's got time to Petrify Filch before he's expelled. I'm only joking --" Ron added hastily as Ginny blanched.

"Somewhere over there," said Ron, pointing along the shelves. "Looking for another book. I think she's trying to read the whole library before Christmas." [Referring to Hermione]

"Hermione, let me read your composition," said Ron desperately, checking his watch.
"No, I won't," said Hermione, suddenly severe. "You've had ten days to finish it --"
"I only need another two inches, come on --"

"I -- don't -- like -- spiders," said Ron tensely.

"If you must know, when I was three, Fred turned my -- my teddy bear into a great big filthy spider because I broke his toy broomstick... You wouldn't like them either if you'd been holding your bear and suddenly it had too many legs and..."

"If, in a month or so, you feel like explaining, you will let us know, won't you?" said Ron irritably [to Hermione].

"D'you think we've got nothing better to do in Potions than listen to Snape?"

"I don't believe it," he [Harry] said as the three of them examined the signature on the note. "He didn't even look at the the book we wanted."
"That's because he's a brainless git," said Ron. "But who cares, we've got what we needed --"

"We'll get you another autograph. Lockhart'll sign anything if it stands still long enough."

"Excuse me? What d'you mean, a bit of whoever we're changing into? I'm drinking nothing with Crabbe's toenails in it --"

"You read too much, Hermione."

"I never thought I'd see the day when you'd be persuading us to break rules."

"Have you ever heard of a plan where so many things could go wrong?"

Ron [disguised as Crabber], who had been gazing at Harry [disguised as Goyle], said, "You don't know how bizarre it is to see Goyle thinking."

"Oooh, it might have hidden powers," said Hermione enthusiastically, taking the diary and looking at it closely.
"If it has, it's hiding them very well," said Ron. "Maybe it's shy."

"Maybe he got thirty O.W.L.s or saved a teacher from the giant squid. Maybe he murdered Myrtle; that would've done everyone a favor..." [Discussing how Tom Riddle got an award for special services to Hogwarts]

"That's a brilliant theory, Hermione," said Ron, "with just one tiny little flaw. There's nothing written in his diary."

"Do you think we should go and ask Hagrid about it all?"
"That'd be a cheerful visit," said Ron. "'Hello, Hagrid. Tell us, have you been setting anything mad and hairy loose in the castle lately?'"

"What does she understand?" said Harry distractedly, still looking around, trying to tell where the voice had come from.
"Loads more than I do," said Ron, shaking his head.
"But why's she got to go to the library?"
"Because that's what Hermione does," said Ron, shrugging. "When in doubt, go to the library."

"Prepare his class," Ron sneered after him [Lockhart]. "Gone to curl his hair, more like."

"Harry! I think Myrtle's grown fond of you! You've got competition, Ginny!"