I have been meaning to mention that the Sundays of Advent have their own, individual blessings to be offered at the conclusion of the liturgy.

For Advent I:
May Almighty God, by whose providence our Savior Christ came among us in great humility, sanctify you with the light of his blessing and set you free from all sin. Amen.

Advent II:
May he whose second Coming in power and great glory we await, make you steadfast in faith, joyful in hope, and constant in love. Amen.