I picked up "In the Woods" by Tana French at the Newberry Book Sale. I had it in my hand and one of the people from my book group said "you should buy that - it's good". And was it.
Speaking of Gillian Flynn, "Gone Girl" is going to be a movie. You can watch the trailer here and I have to say I'm really looking forward to it. I've thought all of Flynn's books would make great movies and maybe this one was the easiest to develop.