DotA 2 is to add a bit of Christmas cheer this month by launching an event called Frostivus, and is to kick off on December 21, 2013. There is not much to go on but we do know that fans will be happy no matter what Valve comes us with, although past events makes us think otherwise.
Looking on the Frostivus page you can see that there is no specific date for this DotA 2 Christmas 2013 event, but because it references the longest night of the year, this would be December 21st.
We are uncertain as to what features Frostivus will bring, but we are sure they will involve collecting and crafting items and then having to drop them off on Frostivus Eve.
What you might find shocking is the truce between Radiant and Dire, although it is nice to see them getting into the Frostivus spirit.
Let us hope that Valve do not ruin this event like they have done so many times in the past. We have even had previous events cancelled, and so let us hope this final DotA 2 event for 2013 goes live and will be enjoyed by fans.