Given my more recent propensity for reading the end of books to see if they are even worth my time, it was hard for me to come up with a book that surprised me. Hah.
From what I remember of this book (which I read several years ago, and only remember that I loved it, and then made John read it, and he loved it too), there is a huge buildup to the climax. What is made clear throughout the novel is that Owen Meany practices a basketball shot over and over and over again with Johnny Wheelwright because he believes this is necessary for his destiny in life. It is also very strongly suggested that the fulfillment of this destiny will result in Owen’s death.
Other than that, the actual moment of “The Shot’s” heroic appearance is bizzarre and completely unexpected. I won’t spoil it. Truth be told, I don’t remember enough detail to do a spoiler any justice anyway. Just know that this was one book I did not read ahead and ruin in advance, and I was surprised.