Introit: Ye men of Galilee, why wonder you, looking up to heaven? alleluia. He shall so come as you have seen Him going up into heaven, alleluia, alleluia. Ps. 44. 2. O clap your hands, all ye nations; shout unto God, with the voice of exultation. Glory be to the Father...- Ye men of...
From the Gospel according to St. Mark 16:14-20: At that time Jesus appeared to the eleven as they were at table: and he upbraided them with their incredulity and hardness of heart, because they did not believe them who had seen him after he was risen again. And he said to them: Go ye into the whole world, and preach the gospel to every creature.
He that believeth and is baptized, shall be saved: but he that believeth not shall be condemned. And these signs shall follow them that believe: In my name they shall cast out devils: they shall speak with new tongues. They shall take up serpents; and if they shall drink any deadly thing, it shall not hurt them: they shall lay their hands upon the sick, and they shall recover. And the Lord Jesus, after he had spoken to them, was taken up into heaven, and sitteth on the right hand of God. But they going forth preached everywhere: the Lord working withal, and confirming the word with signs that followed.
Most Catholic dioceses in the United States transfer today's feast to this coming Sunday (but not all, check your calendar.) Besides making a complete hash out of the Biblical 40 days the resurrected Jesus appeared to his disciples, it sends the message that Catholicism isn't that serious a thing. Going to Mass twice in one week? Such burdens those wicked pharisees lay on our shoulders! Transfer it to Sunday!
I know the stated reason: the bishops want more of the faithful to experience the mystery of today's feast. The kind of Catholic who regularly attends Sunday Mass anyway is also the kind of Catholic who attends Mass on Holy Days of Obligation. Transferring it to Sunday shows that 1) the bishops know a lot of Catholics would deliberately blow off today without a good reason, and 2) they'd rather not put in the work to change that. So the people go along with the soft bigotry of low expectations, so to speak.
In contrast, parishes and dioceses that make tangible demands on their people and instill a sense of discipline... they're never lacking in money or vocations.