Today is this week's second national holiday. Today is the day of the immaculate conception, and is 'celebrated' by many around the world.
Not being very religious myself I had a quick check to see what it really celebrates and it seems it is to celebrate the conception of Mary, mother of Jesus, and is 9 months before her saints day. There is plenty of info on Wikipedia, should you be interested , which says that it was originally the day of the conception of Saint Ann, and this is where it all gets a bit beyond me....
Being a religious day the churches celebrate special masses, and in catholic countries where the day is not a national holiday it is designated a day of special devotion.
Here, many shops will close for the day, while some will still be open to further cash in on the Christmas shopping. For me I'm guessing it'll be a quiet day indoors.