Palm Sunday commemorates Jesus' entrance into the holy city of Jerusalem. He is greeted by the shouts of the crowd: "Hosanna! Blessed is he who comes in the name of the Lord!" By the end of that same week, the crowds will be shouting, "Crucify him!"
For most parishes, the Palm Sunday Mass schedule is the same as the regular weekend Mass schedule.
In the Diocese of Portland, the Chrism Mass is celebrated on the Tuesday of Holy Week. During the Mass, the oils that will be used in the sacraments during the coming year are blessed by the bishop and distributed to parishes. The Mass also brings together clergy from around the diocese, who renew their priestly promises.
Because of the size of the Diocese of Portland, the bishop travels to northern Maine on the Wednesday of Holy Week to celebrate the Mass of the Holy Oils. During the Mass, the oils blessed at the Chrism Mass are presented and distributed to parishes, and the priests of northern Maine renew their promises.
The summit of the liturgical year is the Easter Triduum, which begins on the evening of Holy Thursday and concludes on the evening of Easter Sunday. Though chronologically three days, they are liturgically one day unfolding for us the unity of Christ's Paschal Mystery.
The "three days" are the most holy of the liturgical year because they commemorate the Institution of the Lord's Supper (Eucharist and priesthood) in the Upper Room, with its mandatum/command to "wash the feet" of others in imitation of Jesus Christ; the Passion of the Lord, who suffered and died on the cross on Calvary for the sake of our salvation; Holy Saturday, when we "vigil" in anticipation of the Easter joy that comes to the world through the resurrection of Christ from the dead; and Easter, a day of celebration. The tomb is empty. The Lord has risen! Alleluia!