The Shift of the Magi - S3.E11

Casey tells everyone that they got fabulous gifts for Christmas, so they go out of their way to get her something nice. But when the box arrives, she finds that it's filled with padded hangers. Meanwhile, Jack is forced to play Santa in the hospital - though he later plays Santa out of the goodness of his heart; and Hank realizes that he had made arrangements to work on Christmas months prior.