Ascenday Day, today, is a little like a transfer of Power, kinda.
The Christian church celebrates Ascension day 40 days after Easter, basically since the 14th century. There isn't much in the way of detail, and Luke has most of the story in 24.50-53.
"He led them out as far as Bethany, and lifting up his hands he blessed them. While he blessed them, he parted from them and was carried up into heaven. And they worshiped him and returned to Jerusalem with great joy, and were continually in the temple blessing God."
Jesus, the Resurrected Jesus, had just completed 40 days of coming and going, appearing and disappearing, assuring and equping for what was next. And one thing is clear in his pattern - it's all about the mission to bring souls back to God where they were first together - in the Garden. By this point he had instructed his diciples to "stay and wait" for "power from on high." (Luke 24.49) They didn't know, they couldn't know the Spirit's Power, sent from Jesus, would distribute all that Christ had won on the cross, and guarntee it all in the resurrection.
We're here because of that "transfer of power." We have the freedom to live freely because of that "transfer of power." We have the assurance we've been designed and redeemed to live forever because of that "transfer of power."
What a life we live as a result of Jesus' ascension and the power of the Spirit that came after that... but that's getting ahead of the story a litle bit...