USPS is closed on Christmas Eve, but they do have a few special services that can be used for last-minute gifts. They have a special "Santa's Sleigh" service where you can send packages via overnight shipping and have them delivered by Christmas Eve. However, this service is more expensive than regular shipping. They also have a special "Santa's Helper" service where you can have a USPS employee personally deliver your package to the recipient on Christmas Eve. This service is also more expensive than regular shipping.