Some interesting Christmas facts for kids include the original meaning of Christmas (that is, the celebration and story of the birth of Jesus Christ in Bethlehem) and the names of Santa's original eight reindeer: Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner (or Donder) and Blitzen. The ninth and perhaps most famous reindeer, Rudolph, did not exist before the song about him was released.
Children might also be interested in some facts about their favorite Christmas confections. Christmas pudding, for instance, while it has always contained raisins and some kind of alcohol, was originally more of a soup than a cake. Its origin is attributed to the ancient Celts and their dish, "frumenty." Mince pies, meanwhile, are traditionally considered a good luck charm if one is eaten on each of the twelve days of Christmas (starting on Christmas Eve), but are an omen of bad luck if they are eaten at any other time of the year.
Another interesting Christmas fact is that it was effectively banned in 1647 by Oliver Cromwell, the leader and spokesman of the Puritans who later colonized America. The ban, which outlawed any kind of merriment on the holy day, was not lifted until 1660.
Finally, kids in the United States may be interested to find out that in many countries, including Egypt and Ethiopia, Christmas Day is not celebrated until January 7.