Affiliation: Order of the Phoenix
George Weasley enters this last book with a bang – a terrible bang that blasts his ear off. He features in the Order's plan to get Harry safely out of Privet Drive, and ends up as one of the casualties. He suffers an injury from a Sectumsempra curse from Severus Snape (we find out too late that Snape didn't actually mean to injure George, and was instead trying to discreetly hit another Death Eater). However, being George Weasley, he recovers quickly, and is immediately able to crack a joke at his own expense.
This is consistent with his character as we've known him before; on the whole, we don't see George or his twin, Fred, that much. But we can figure that they're going through tough times, like everyone else, and growing up into real adults in Book 7 and throughout the series. George has to deal with the loss of his ear first, and then with the devastating death of Fred. So it isn't hard to imagine that, by the end of the book, he's an older, more somber guy (but, we hope, still with his sense of humor and love of life).