The Social Network- written by Aaron Sorkin, based on "The Accidental Millionaires" by Ben Mezrich
Perhaps an easy get; it's razor sharp writing has been universally acknowledged. Tomorrow night might be a more telling big win for team Social Network with the WGA awards, in which it's main competition The King's Speech will be nowhere in sight.
My WGA predictions:
Best Original Screenplay: The Kids Are All Right
Best Adapted Screenplay: The Social Network