It's Christmas Eve, and there's lots to be done between seeing relatives, wrapping presents, preparing tomorrow's big dinner - and of course tracking Santa.
In fact, keeping your eye on Santa's whereabouts is important because if you know where he is, you know when to go to sleep.
That's because the team from the North American Aerospace Defense Command (NORAD) - or the US Air Force to you and me - have an important job at Christmas: tracking Santa.
They can draw on their multi-billion dollar equipment, which includes satellites, jets, hi-tech cameras and radar, which helps them keep their eye on the North Pole native.
And luckily for you, they make their search for Santa public, so you can see exactly where he is around the world - and make sure you're in bed on time.
That's more important than ever - if you don't get to bed, he won't leave any presents for you.
How do I track Santa?
To access these hi-tech controls, log-on to the Norad Santa website . This year they'll have loads of pre-Christmas fun in the run-up to the big day.
On Christmas Eve, you can see on a live map where Santa is in the world, and how long you have to get to bed.
Why do the US Air Force track Santa?
The story began back in 1955. An advert that went in a local paper was misprinted, which meant children calling Santa got through to the US Air Force Continental Air Defense Command Operations Center.
They loved the idea, and have carried it on ever since. Now they publish his whereabouts online, and show videos of him arriving at key locations around the world.
To track Santa, go to noradsanta.org
