Gacked from mistraltoes and kerravonsen. Like them, I won't restrict myself to one sentence.
From Sunday Morning til Saturday Night (Sweet Valley High):
“I’m not going to tell you teenagers not to have sex. Heck, if you all got really into it, Sweet Valley High could have a truly great football team in fifteen years time. But make it American sex, not that European stuff.”
From Hermione Granger and the Stone of Blood (Harry Potter):
“But how can I be a grown woman when Harry and Ron are still boys? Unless... Of course! Why didn’t I see this before?! My own magic must have effected the transformation! You must have seen this happen before, haven’t you?"
“Every year. It’s scarcely high magic.", Professor McGonagall explained. “Even Muggles can do it. I must say that I am impressed by one thing, though. It’s been quite a while since a girl aspired to my job. Lately the Sorting Hat seems to put any girl with ambition beyond marrying a wizard into Slytherin.”
From Vila the Puppeteer (Blake's 7):
“Can I have your cherry?” Avon asked Soolin.
“If I can have your stalk," she replied.
From Acorn and Oak (Xena):
“Take me for example!" Claudius went on, “I may be a complete military ignoramus, but my father, he was a great general! One of the very best! Did you know he practically conquered Germany? At least until he ran into Xena, who told him that if he knew what was good for him, he'd take his whole army, turn around, and go straight home.”
“So what happened?”
“Well, apparently, he knew what was good for him.”
From The Red Room (Star Trek: Voyager):
Janeway studied her bare backside in the mirror. There were well-defined stripes in a yellowish hue, with erratic splotches of feminine pink, masculine blue and mysterious black. All morning she had been compulsively looking at it in the mirror. Her bruises were as beautiful as flowers tattooed on her skin.
From Swamp Weed II (Blake's 7):
“It’s called being ‘drawn’”, explained Carnell, observing the darkly comical efforts to remove the blood stains - at least, he hoped they were blood stains - from the carpet and the walls. “Hung, drawn and quartered. An ancient punishment for traitors.” He paused thoughtfully and then asked: “Do you know how to bind someone's limbs so that they fly off like that, instead of the hands and feet coming off?”