Pentecost

The Acts of the Apostles recounts the story of the original Pentecost. Jews from all over were gathered in Jerusalem to celebrate the Jewish feast. On that Sunday, ten days after the Ascension of Our Lord, the Apostles and the Blessed Virgin Mary were gathered in the Upper Room, where they had seen Christ after His Resurrection:
"When the day of Pentecost came, they were all together in one place. Suddenly a sound like the blowing of a violent wind came from heaven and filled the whole house where the were sitting.  They saw what seemed to be tongues of fire that separated and came to rest on each of them.  All of them were filled with the Holy Spirit and began to speak in other tongues as the Spirit enabled them." ~Acts 2:1-4
Christ promised His Apostles that He would send His Holy Spirit, on Pentecost, they were granted the gifts of the Spirit. They began to preach the Gospel in all the languages that the Jews who were gathered there spoke, and about 3,000 people were converted and baptized that day.

The Birthday of the Church

That is why Pentecost is often called "the birthday of the Church." On this day, with the descent of the Holy Spirit, Christ's mission is completed, and the New Covenant is inaugurated. It's interesting to note that St. Peter, the first pope, was already the leader and spokesman for the Apostles on Pentecost Sunday.
Now there were devout Jews from every nation under heaven living in Jerusalem. And at this sound the crowd gathered and was bewildered, because each one heard them speaking in the native language of each. Amazed and astonished, they asked, "Are not all these who are speaking Galileans? And how is it that we hear, each of us, in our own native language? All were amazed and perplexed, saying to one another, "What does this mean?"
But others sneered and said, "They are filled with new wine."
But Peter, standing with the eleven, raised his voice and addressed them, "Men of Judea and all who live in Jerusalem, let this be known to you, and listen to what I say. Indeed, these are not drunk, as you suppose, for it is only nine o’clock in the morning. No, this is what was spoken through the prophet Joel:

“In the last days it will be, God declares that I will pour out My Spirit upon all flesh, and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams. Even upon My slaves, both men and women, in those days I will pour out My Spirit; and they shall prophesy. And I will show portents in the heaven above and signs on the earth below, blood, and fire, and smoky mist. The sun shall be turned to darkness and the moon to blood, before the coming of the Lord’s great and glorious day. Then everyone who calls on the name of the Lord shall be saved.”

In years past, Pentecost was celebrated with greater solemnity than it is today. In fact, the entire period between Easter and Pentecost Sunday was known as Pentecost (and it still is called Pentecost in the Eastern churches, both Catholic and Orthodox). During those 50 days, both fasting and kneeling were strictly forbidden, because this period was supposed to give us a foretaste of the life of Heaven. In more recent times, parishes celebrated the approach of Pentecost with the public recitation of the Novena to the Holy Ghost.

While most parishes no longer publicly recite this novena, many individual Catholics do.
You will always find this Novena on this blog when the time comes as long as I have breath.

Prayer to the Holy Spirit for a Favor

O Holy Spirit, You are the Third Person of the Blessed Trinity. You are the Spirit of truth, love and holiness, proceeding from the Father and the Son, and equal to Them in all things. I adore You and love You with all my heart. Teach me to know and to seek God, by Whom and for Whom I was created. Fill my heart with a holy fear and a great love for Him. Give me compunction and patience, and do not let me fall into sin.
Increase faith, hope, and charity in me and bring forth in me all the virtues proper to my state of life. Help me to grow in the four cardinal virtues, Your seven gifts, and Your twelve fruits.
Make me a faithful follower of Jesus, an obedient child of the Church, and a help to my neighbor. Give me the grace to keep the commandments and to receive the sacraments worthily. Raise me to holiness in the state of life to which You have called me, and lead me through a happy death to everlasting life. Through Jesus Christ, our Lord. Grant me also, O Holy Spirit, Giver of all good gifts, the special favor for which I ask [name the favor here], if it be for Your honor and glory and for my well being. Amen.
Glory Be, etc.

Holy Spirit, thank You for Your constant comings—sometimes when we pray for the coming, sometimes when we least expect it, You come. We need Your Spirit coming anew into our daily living. Come, great Spirit, Come! Amen.

Spirit of the Living God, fall afresh on me. Spirit of the Living God, fall afresh on me. Bend me, mold me, fill me, use me! Spirit of the Living God, fall afresh on me!