The Twelve Days of Christmas, or Christmastide, ended yesterday. If you're like me, you probably have an exorbitant amount of Christmas lights and decorations to take down now (although it's only bad luck to leave up decorations past yesterday in the UK)!
Today, Epiphany, is the Christian holiday that recognizes the Incarnation of Jesus Christ (in other words, that God made Jesus, a divine being, into man). Countries all over the world recognize this holiday with traditional and modern celebrations.
In America, the people who celebrate Epiphany the most are in New Orleans. They use this date to mark the beginning of Marti Gras and "King Cake" season. Believe it or not, King Cakes are vaguely related to the birth of Jesus- inside the large cinnamon roll cake is a small trinket, usually a plastic baby doll representing the baby Jesus. Whoever gets the piece of cake with the trinket in it is named the King or Queen of the day and buys the cake for everyone the next year.
... I don't know how finding baby Jesus in your cake and becoming royalty for the day is connected to the Incarnation, but to each his own, I suppose! :)
Hope you have a happy day no matter what you do!