It was a dark and stormy night
I was always hoping Snoopy would finish that book.
It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to heaven, we were all doing direct the other way, …, Charles Dickens, A Tale of Two Cities.
I have to third this one. It grabbed me and sucked me right in.
Many others have gotten that far, too.
The Bulwer-Lytton Competition is the appropriate link for this thread.
The Time Traveller (for so it will be convenient to speak of him) was expounding a recondite matter to us.
–The Time Machine
No-one would have believed in the early years of the twenty-first century, that our world was being watched by intelligences greater than our own.
–The War of the Worlds
Why yes, I am an HG Wells whore, why do you ask?
Far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the Galaxy lies a small unregarded yellow sun.
–Go on then, guess! 
“Marley was dead: to begin with.” – Charles Dickens, A Christmas Carol
Well then, I salute your excellent taste (pun intended).
“In five years the penis will be obsolete,” said the salesman.
John Varley, Steel Beach
It’s also the first line of A Wrinkle In Time.
The first line of practically any of Terry Pratchett’s Discworld novels.
It is a truth universally acknowledged, that a single man in possession of a good fortune must be in want of a wife.
(Jane Austen, Pride and Prejudice)
I am doomed to remember a boy with a wrecked voice - not because of his voice, or because he was the smallest person I ever knew, or even because he was the instrument of my mother’s death, but because he is the reason I believe in God; I am a Christian because of Owen Meany.
(John Irving, A Prayer for Owen Meany)
“In our family, there was no clear line between religion and fly fishing” Norman Maclean in A River Runs Through It . That line sent chills up my spine and I was hooked. (no, no pun intended but I’ll let it stand.)
Antigen, I second the opening line of A Prayer for Owen Meany.
Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun.
“It was love at first sight. The moment Yossarian saw the Chaplain he fell in love with him.” – Catch-22, Joseph Heller
“What’s it going to be then, eh?” – A Clockwork Orange, Anthony Burgess
The human race, to which so many of my readers belong, has been playing at children’s games from the beginning, and will probably do it till the end, which is a nuisance for the few people who grow up. – G. K. Chesterton , The Naopleon of Notting Hill
"Sherlock Holmes took his bottle from the corner of the mantelpiece and his hypodermic syringe from its neat morocco case. " The Sign Of Four.
“I was bored, I believe, when the nasties were still booming us
Led by Madolf Heatlump (who only had one)
Anyway, they didn’t get me.”
- John Lennon, “In His Own Write”
“Riverrun, past Eve and Adam’s, from swerve of shore to bend of bay, brings us by a commodious vicus of recirculation back to Howth Castle and Environs.”
Finnegans Wake by James Joyce.
“What’s it going to be then, eh?”
There was me, that is Alex, and my three droogs, that is Pete, Georgie and Dim, Dim being really dim, and we sat in the Korova Milkbar making up our rassoodocks what to do with the evening, a flip dark chill winter bastard though dry.
Oops, I missed BrainGlutton’s earlier post. Sorry, BG.
anyhoo:
“Call me Ishmael”