Chalk was blessed and given out at the end of Mass today. Everyone was invited to take some home to use to pray for, and bless their home. At the beginning of the year, following Catholic tradition, we pray for the homes of the parish and of all our people.
If you would like to join in with this tradition here is what to do:
A marked doorway of one of our family’s homes
Using blessed chalk, (or if not blessed any chalk) either above the door, outside, or at the side of the door outside or inside, the markings 20 + C + M + B + 12 are made, or (20+K+M+B) 20 and 12 being the year, C (K), M, B being the intitials of the traditional names of the wise men, Caspar, Melchior and Balthasar, they can also stand for Christus Mansionem Benedicat, the Latin words meaning, May Christ bless this home.
If you prefer you may instead make a simple cross mark with chalk +
These prayers are used in our parish:
God of heaven and earth, you revealed your only Son to every nation by the guidance of a star. Bless this home and all who live in it. Fill us with the light of Christ, that our concern for others may reflect your love. We ask this through Christ who dwells among us. Amen.
Loving God, may all who come to our home this year rejoice to find the love of Christ here; and may we seek and serve, in everyone we meet, that same Jesus who is your incarnate Word, now and forever. Amen.
If you use this to do a blessing of your home we’d love you to send us a photograph of the 20 + C + M + B + 12 marked doorway.
And here is the 2013 update. And here is the 2014 update 🙂
St Chrysostom's Church News and Views 
(To avoid confusion, this other post be may deleted. This one is accurate.)
We had our priests come and bless our home for Epiphany. How do I send a picture? Perhaps being FSSP (traditional Latin Mass) priests, they write the year in Roman numerals, so the inscrptions over the doors appear as MM+C+M+B+XII.
I have had this on my door for around 20 years. I just change the numbers every Jan first
I was grateful to find your website when I Googled 20 C M B 12 because I could not remember the Latin words for May Christ bless this home. A couple of years ago I started doing this after being reminded in another publication–this is a ritual that brought back happy memories from my childhood in MN
So someone chalked 20+c+m+b+08 on the threshold to my condo. What would the 08 represent?
That would indicate a kind person blessed your condo in 2008.
Maybe January 2016 will be the time to have the blessing renewed!