This is a Biblical scene which always excited me in both art and school nativity plays. This is when the Angel Gabriel appears to Mary of Nazareth to tell her that she will give birth to the son of God, and that his name shall be Jesus, or Iesus, or Emanuel, depending on what you are reading.
I recall playing the part of an angel in my school nativity play, and my first entrance was during this scene. The angels were in three scenes, and sang a different song in each. Every song would have a solo part at the beginning, followed by the group part. I wanted to be the Angel who sang to Mary, but alas, I was not. That part went to a girl called Jessica. Or a boy called Matthew, I can't remember. I did however, get to sing a solo to the three wise men. I can still remember the words and the tune, which was devised by the pianist and music teacher; Mr Whitehall.
'Wise men, wise men, listen to me wise men,
Don't be afraid, I've got something to say.
Herod is a wicked king and he will try to harm the child.
You must not go back to him, go home another way...'
Here are some of my favourite painted versions of the Annunciation. I find myself really enjoying the John William Waterhouse version, as well the Fra Angelica, obviously.