Afraid I can’t answer any so far. But here’s one that’s completely unforgettable.
My mother was the village whore and I loved her very much.
Steel Beach by John Varley
A few of my own:
Z1: There was once a boy named Milo who didn’t know what to do with himself - not just sometimes, but always.
Z2: It was a dark and stormy night. (Yes, there really is a popular book that starts that way)
Z3: Once upon a time, sixty years ago, a little girl lived in the Big Woods of Wisconsin, in a little grey house made of logs.
Z4: Clare: The library is cool and smells like carpet cleaner, although all I can see is marble.
Z5: “I’ve watched through his eyes, I’ve listened through his ears, and I tell you he’s the one. Or at least as close as we’re going to get.”
Z6: “Death,” the proprietor said clearly, showing the stone.
Z7: Before she went to the launch site, Helena Lyakhov always went through the same ritual.
Zev Steinhardt
Z2 is A Wrinkle in Time. I considered that one myself.
Z5 is Ender’s Game.
Oh, and I believe Z3 is Little House in the Big Woods.
Here’s one:
The Phantom Tollbooth.
Props to silverfish for getting Through the Looking-Glass.
FP3: On Mondays, Wednesdays, and Fridays it was Court Hand and Summulae Logicales, while the rest of the week it was the Organon, Repetition and Astrology.
FP3: The Glass Bead Game?
To complete the original 10
An American Tragedy by Theodore Dreiser
The Time Taveller’s Wife.
Ooh! Jane Austen, Northanger Abbey.
MPK 1: One may as well begin with Helen’s letters to her sister.
MPK 2: [Character name], who was usually very late in the mornings, save upon those not infrequent occasion when he stayed up all night, was seated at the breakfast table.
Caddie Woodlawn?
WAG: Piers Anthony’s On A Pale Horse.
Nope. (Miss Purl McKnittington is spot on about Northanger Abbey, though.)
Howards End, right?
FP4: 1801 – I have just returned from a visit to my landlord – the solitary neighbor that I shall be troubled with.
Whoo!
Ayuh.
One more!
MPK 3: Mrs. [Character name] said she would buy the flowers herself.
Phantom Tollbooth, Juster
Little House In The Big Woods, Wilder
F1: Claudia knew that she could never pull off the old-fashioned kind of running away.
F2: One night after dinner when David was reading Doctor Dolittle in the Moon and his father was reading the newspaper, and his mother was darning socks, his father suddenly exclaimed; “Well, now, that’s very odd!”
The Once and Future King?
Or The Sword In The Stone, depending on if she has the collected version or not! 
Yep, stargazer and Fenris have got it.
Um… From the Mixed-Up Files of Mrs. Basil E. Frankweiler?
Mrs. Dalloway?
(Not sure about either of those, so will hold off on posting new ones.)