Liturgy is "the participation of the People of God in 'the work of God'"; It is the "exercise of the priestly office of Jesus" in which God is worshiped and adored and people are made holy. God begins the work of sanctifying people in time and space and brings that work to completion. Those who respond to God in worship and in service are given the privilege of becoming co-workers in the divine plan.
—
From Built of Living Stones
Liturgical Year
Advent: First Sunday of Advent through December 24th
Christmas: December 25th through The Feast of the Baptism of the Lord
Ordinary Time: Between Christmas (the Feast of the Baptism of the Lord) and Lent (Ash Wednesday)