What to wear as Jack Torrance: Pair a red plaid shirt under a red corduroy jacket with jeans, and carry an ax. To take your costume to the next level, either make it look like your clothes and face are covered in frost (Jack's garden maze look) or attach a piece of cardboard to your chest to make it look like you're peeking out of a door.
How to act as Jack Torrance: Out of your damn mind.