The Ascension of the Lord
(from www.jesuschristsavior.net/Ascension.html)

"But you shall receive power when the Holy Spirit has come upon you; and you shall be my witnesses in Jerusalem and in all Judea and Samaria and to the end of the earth." And when he had said this, as they were looking on, he was lifted up, and a cloud took him out of their sight. And while they were gazing into heaven as he went, behold, two men stood by them in white robes, and said, "Men of Galilee, why do you stand looking into heaven? This Jesus, who was taken up from you into heaven, will come in the same way as you saw him go into heaven."
Acts of the Apostles 1:8-11

The Ascension of Our Lord Jesus Christ is described in the above passage from the Acts of the Apostles, and is also noted in Mark 16:19 and Luke 24:50-53. Jesus refers to his Ascension in the Gospel of John when he tells Mary Magdalene, "Stop holding on to me, for I have not yet ascended to the Father, but go to my brothers and say to them, I am ascending to my Father and your Father, to my God and your God". (John 20:17).

Before his Ascension, Christ spent forty days teaching the Apostles and disciples about the Kingdom of God (Acts 1:3). The Lord informed them that they would receive power from the Holy Spirit to be his witnesses to the ends of the earth (Acts 1:8). The Ascension occurred at Bethany on the Mount of Olives (Luke 19:29).

Jesus Christ made multiple appearances in several locations to his disciples for forty days following his Resurrection. For example, Jesus appeared first to Mary Magdalene in Jerusalem (Matthew 28:9-10, Mark 16:9, John 20:14-17), to two disciples on the Road to Emmaus (Luke 24:13-32), to Simon Peter (Luke 24:34, First Corinthians 15:5), to his disciples in the evening of that first day (John 20:19), and a week later to Thomas and the disciples (John 20:26). He appeared to James (First Corinthians 15:7), and to Peter and the Apostles in Galilee (Matthew 28:16-20, John 21:1).

His glorious Ascension signified the completion of his time on earth, which is celebrated by the Church forty days after the Resurrection and ten days before the Pentecost, the coming of the Holy Spirit. Our Lord Jesus Christ gave us hope by promising that "when I go and prepare a place for you, I will come again and will take you to myself, that where I am you may be also" (John 14:3).


Some Resources for Ascension Day
A Prayer
The Ascension (UMH 323)
Hymn
. Verses - Hymn: Hail the Day that Sees Him Rise (UMH 312)

See also this Article:
The Ascension of Jesus from Wikipedia - not a "faith based" article but it does present many traditions