Serenity! Not really out now, but out tomorrow. Even if you don't wanna see it, buy a ticket for it and sneak into something else....
If I were going to fill up an afternoon with movies, I would go to see Serenity, then The Corpse Bride, then A History of Violence. Substitute MirrorMask for History of Violence, if you are lucky enough to have it playing in your down. It doesn't look like MirrorMask will even be playing in this state =(