For us Orthodox, Christmas is actually 12 days, and from start to finish there is a progressive revealing that occurs.
On December 25th we celebrate the nativity of Christ. This celebration of the birth of Christ is a celebration of God being with us in the world.
On January 1st, the 8th day of Christmas, we celebrate the circumcision of Christ. The significance of this day is that it would have been the day that Christ officially received His name, Jesus. The name Jesus means "Salvation of God". This celebration of Christ's circumcision is a celebration of God's name being revealed to us.
On January 6th we celebrate the baptism of Jesus, or theophany. On theophany, worship of The Trinity was made manifest. This celebration of Christ's baptism is a celebration of both God being made visible, and The Eternal way, which is worshipping God in Spirit and Truth, aka The Trinity.
Sadly this ancient tradition and the mystagogy that it was intended to facilitate the communication of has largely been lost by most protestant/evangelical churches, who in their zeal to seperate themselves from Roman Catholicism discarded the church calendar.
Well, to those of who still use the church calendar, it is very useful as a learning tool. Besides the fasts and the feasts, every day there is a saint to remember making it a good way to learn church history. Besides that, there are scripture readings every day that are intended to flesh out the typography of the faith and reveal Christ.
To those evangelicals and protestants who don't have the calander, you're really missing out! It is a useful teaching tool, and it brings people together.
To those Roman Catholics and Orthodox Catholics who have the calendar, consider making it a part of your daily life.
Sure, one could say that all days are equally holy, but lets not forget that the intent here with the calendar is to edify. It is there to make use of, so why not? If it isn't your cup of tea, that is fine, but observing the calendar is still a good practice. For some people, it helps them to be mindful of God, and what believer would count that as a bad thing?
Happy new year, everybody.