While you can't judge a book by its cover, you can judge a book by the first sentence.
From Margot Hunt's Best Friends Forever
From Kathy Reichs and Brendan Reichs' Virals: Terminal
From Rick Riordan's Heroes of Olympus: The Son of Neptune
From Anthony Horowitz’s Alex Rider: Secret Weapon
From Maria Semple’s Where’d You Go, Bernadette
From Tony DiTerlizzi and Holly Black's The Spiderwick Chronicles: The Seeing Stone
From Rick Riordan's The Heroes of Olympus: The Lost Hero
From Nicholas Spark's Two by Two
From Bill Cosby's Fatherhood
From Eion Colfer's Artemis Fowl: The Arctic Incident
From Katherine Paterson's Bridge to Terabithia
From Tony DiTerlizzi and Holly Black’s The Spiderwick Chronicles: The Field Guide
From Rick Riordan's Magnus Chase and the Gods of Asgard: The Ship of the Dead
From Carol Burnett's In Such Good Company
From Sue Halpern's Summer Hours at the Robbers Library
First Sentence of a New World 