January 6th is a National Holiday in Colombia, and it officially marks the end of the holiday season. This particular holiday is known as the Día de los Reyes Magos -- Three Kings Day or the Epiphany. There is a great explanation of the evolution of the celebration of the Epiphany at the following site.
However, the key here is that in Hispanic countries, January 6th has become known as Three Kings Day. It is a commemoration of the day when the 3 Wise Men who had followed the Star of Bethlehem, arrived bringing their gifts of gold, frankincense, and myrrh.
This holiday is widely celebrated, however, while it is a big deal in Mexico, Spain and other countries, it is less of a big deal in Colombia. There is a tradition that the Reyes Magos give gifts (like Santa), but in Colombia this tradition is usually only observed by the few people that have money left from their Christmas Eve gifting.
While this day should mark the end of the partying season, Colombians have a hard time letting go of anything that allows them to party. After all, Colombia was found to be the 6thhappiest place on earth -- having lost a few spaces from last year's 2nd place showing. So, in reality, it is the beginning of a second wave of partying that includes things like the Carnaval in Barranquilla and any number of Férias, Festivales, and Beauty Contests -- some of which I'll be discussing in the upcoming days and weeks.