Also known as Feast of the Epiphany, Three Kings Day, or Theophany, this Feast is a great and very important Feast in memory of Jesus showing His glory in 3 ways: as an infant to the Magi, at His baptism, and at His first miracle at the wedding in Cana. So important is this Feast, that it is a Holy Day of Obligation in many parts of the Catholic world, though not presently in the United States. The symbols of the day are the same as those mentioned on the page describing Twelfthnight.
On the morning of the Feast of the Epiphany, children in some households will wake to see what gifts had been left by the Magi (or La Befana) during the night.
At today's Mass, there will be a blessing of gold, frankincense, myrrh, Epiphany Water, and, after Communion, a blessing of chalk. Bring small special items of gold to have with you during the Mass, and they will be blessed if they are exposed as you sit in your pew with them (wedding rings, rosaries, an heirloom piece of gold jewelry, for example).
When Mass is over, you will take some of the blessed chalk, frankincense, myrrh, and Epiphany Water home with you, so it's good to bring a container to transport Holy Water and one to put some grains of incense and a piece of chalk into. (Note: if you can, take and keep 5 pieces of blessed incense for your Paschal Candle this Easter),
When you get home, sprinkle some Epiphany water (otherwise and afterwards used as regular Holy Water) in the rooms of your house to protect it and bring blessings. This Holy Water recalls the waters of the Jordan, and is a visible reminder of Christ's Divinity, of Jesus's revealing Himself as God at His Baptism, when were heard the words from the Father: "This is My beloved Son, in Whom I am well pleased."