For slightly older kids who don’t believe in Santa, keeping them entertained can be a bit more difficult.
Musical instruments are always popular and will keep them entertained (though you might want to avoid drumkits).
Let them do what they want but try not to let them spend hours in front of the TV or playing video games.
Get them involved in the preparation (decorating the house, laying the table, simple cooking). They’ll feel involved and useful instead of feeling as if they’re getting under your feet.