I had the rare good fortune to be working at a Sam's Club in a rather small town (Fairbanks, Alaska) on the day that Goblet of Fire was released. I routinely came in at 5 in the mornings. By the time I took my first break at ten, the stacks that had been gloriously full in the morning were now considerably diminished, and instead of taking my well-earned rest, I nipped over to the horde, snagged myself a copy, and bought it. I got a few chapters through that day; by the time I left around two-ish, the books were gone. My father came home disappointed that he hadn't gotten a copy. (He's honorary grandfather to a few dozen small children between the ages of zero and nineteen, and routinely has at least five clinging to his legs at all times.) I handed mine over as soon as I was done reading it, and haven't recovered it yet.
In book news, I hear that Lois McMaster Bujold is about thirteen chapters along on writing the latest Vorkosigan book (if you are unfamiliar with her, I'm going to have to hurt you -- four Hugos and counting), and Diane Duane is polishing up the fourth book in the Tale of the Five.