There is probably no need to say this since it is common knowledge (and I certainly do not want to offend anyone by seeming condescendingly know-it-all), but almost all film awards (including the Academy Awards aka the Oscars) are given out to films of a specific calendar year. It is very beneficial for an award contender to come out in the last two months of the year so as to catch the attention of Oscar voters, but it is equally important to have the movie screen for critics and Academy voters before the year's end in order to make sure people have a chance to vote for it.
Every year, filmmakers rush to get their movies done in order to get a screening in the prime mid-November to mid-December time slot, but this year this seems to be a bigger issue than usual. Three Oscar winners have been racing against the clock to get their high-profile films ready to show before Christmas. Quentin Tarantino's Django Unchained and Kathryn Bigelow's Zero Dark Thirty have still not been shown to anyone, allegedly because they are not completed (shooting is done, of course, but editing, visuals, and score are not). The big-budget musical adaptation of the literary classic Les Miserables was also on this list right up until it aired on the afternoon of yesterday, Friday the 23rd.
Here is the interesting part: Collider reports that Emmy and Oscar winning Director Tom Hooper had apparently not finished the film until around 2 am on the morning of the day it was scheduled to have its first screening! That is really cutting it close. 10 hours is not a lot of wiggle room.
For a first screening, film distributors obviously make sure to stock the audience with those most likely to adore the film; this effect was probably amplified by the fact that you would have to have pretty high anticipation to get to a packed theater in the middle of New York City the day after Thanksgiving. In other words, take this next statement with a grain of salt. That said, Les Miserables apparently had was incredibly well-received. The audience applauded after every musical number (which probably got old pretty quickly) and then spent fifteen minutes on a standing ovation (the entire cast was out on stage, which certainly helped matters).