The liturgical calendar of the Catholic Church begins with Advent in late November/early December, rather than on January 1st like our traditional Roman calendar. The year is split into various "times," allowing the Church to guide her people through the life and ministry of Christ and appropriately reflect upon significant events accordingly.
Advent
Advent is a time of preparation and anticipation for the arrival of Jesus; not only are we to prepare for Him in remembrance of His birth, but we are also to take this time to prepare for the Second Coming of Christ. Advent consists of a period of time containing 4 Sundays (and their weekdays) beginning 4 Sundays before Christmas and ending on December 24. It is common practice to use an Advent Calendar during this season, with the opening of each date as a symbol of our anticipation. While some Advent Calendars offer candy rewards inside each day, it is also suggested that each day be filled with a new reflection; click here to see the United States Conference of Catholic Bishops' Advent Calendar for reflections.
The Christmas season begins with vigil Masses on Christmas Eve (December 24) and ends on the Feast of the Baptism of the Lord. It is during this time that we are to reflect upon Jesus' full humanity and full divinity, as He is named Emmanuel ("God-with-us") and fully partakes in our state of being so that He may die in our salvation.
This first part of Ordinary Time involves readings from Jesus' childhood through the early part of His ministry.
Lent is a time of reflection and consideration of our baptismal promises. The 40 days of Lent (excluding Sundays) involve sacrifice and self-reflection; Catholics ages 18-59 are expected to fast and abstain from meat on Ash Wednesday and Good Friday, and to abstain on all Fridays during Lent. It is also common practice to make a sacrifice for the Lenten season, such as giving up certain foods (to become more thankful for what we have and what Jesus' suffering has given to us) or activities (to make more time for Scripture and prayer, or to attempt to cut down on activities that distract us from our Faith); it is also common to take on more responsibility for one's Faith rather than sacrificing goods or pleasure, such as setting aside more time for prayer and Scripture-reading each day. Lent prepares us to fully participate in the celebration of Christ's Resurrection and thus our ultimate salvation.
Holy Thursday
The Triduum is the whole of our faith in three days - the Paschal Mystery in its essence. It begins with Jesus' gift of himself in the Eucharist and includes his command that we serve others as he has served; that is, with his whole life, even in the grittiest dimensions of human life.
Prayer Intentions for the Day: vocations, service to the poor, faith in the unseen presence of God in the Eucharist and all the sacraments
Good Friday
The Passion encompasses every kind of suffering - physical, psychological, shame, humiliation, mockery, and more - including death. In Jesus' case, it made no sense cosmically for a totally innocent man to become a scapegoat for us and endure the unmerited suffering as an archetype for all our suffering.
Prayer Intentions for the Day: victims of violence, bullying, scapegoating, those suffering physical and mental illness
Holy Saturday and Easter Vigil
At the end of the normal course of human life (that is, death), all seemed to be lost. And from a strictly human, earthly perspective, it was. The resurrection came out of the blue, just as creation itself did in the first place. Unexpected, beyond our imagining, the resurrection of Jesus makes it possible for us to hope for eternal life.
Prayer Intentions for the Day: hope in what appears to be a hopeless situation, gratitude for the gift of life, trust in God's mercy
"The Mystery of the Cross and Resurrection assures us, however, that hatred, violence, blood, and death do not have the last word in human affairs. The final victory is Christ's, and we must start afresh from him, if we wish to build a future of authentic peace, justice, and solidarity for all." 1
The Easter season begins with the Easter Vigil Mass,
1 - St. John Paul II, Reflections on the Triduum