Yeah, so we no longer have an Octave of Pentecost, but that's not going to stop us. Go read Mike Aquilina on the Church Fathers and Pentecost. His blog should be one of your daily stops anyway.
Writing about 198 A.D., Tertullian testified that Pentecost was one of the great feasts of the Christian year. It was, after Easter, the time most appropriate for baptism.
At the end of the fourth century, the pilgrim Egeria tells us in great detail how the Church of Jerusalem kept the feast, perhaps when St. Cyril was bishop. The celebration lasted all day, from the first glimmer of dawn till way past bedtime, and the great throng of Christians proceeded in stations to all the holy places of Jerusalem. Round midnight, Egeria said, on Mount Zion, “suitable lessons are read, psalms and antiphons are said, prayer is made, the catechumens and the faithful are blessed, and the dismissal takes place. And after the dismissal all approach the bishop’s hand, and then every one returns to his house … Thus very great fatigue is endured on that day, for vigil is kept at the Anastasis [Church of the Holy Sepulchre] from the first cockcrow, and there is no pause from that time onward throughout the whole day, but the whole celebration lasts so long that it is midnight when everyone returns home after the dismissal has taken place at Zion.”
Next time you hear kids ask, “Is Mass almost over?” you can tell them how it was in great-great-great-great-(etc.)-grandpa’s day.