In the older, traditional form of the Roman Rite, today is the Feast of the Immaculate Conception, with a commemoration of the 2nd Sunday of Advent.
In the newer, Novus Ordo, today is the 2nd Sunday of Advent. Immaculate Conception is displaced.
Were there any good points in the sermon you heard for your Sunday Mass of obligation?
Let us know.
You could add your good points from sermons for the Immaculate Conception, if you went to Mass on Monday.