The Celebration of Christmas is actually the celebration of his (Prophet) Jesus birth, however it isn't accurate, (if you want to argue about date is accurate check Wikipedia!)
So, they take a month, putting decoration, and people go crazy in malls, where everyone suppose to buy presents (except for the poor and cheap ass), that when they have this 'black Friday' for sale.
So, they celebrate the birth of 'god' or 'son of god' depends on which sect they belong too, they make songs and re-act of god's birth or son of god's birth, and imaginary story about man name Santa, although the Santa been said represent the three wise men who want to see the 'god' or 'son of the god'
sadly, we in Islam can't even say 'happy Christmas' due to the fact it has conflict with teaching and number ONE principle "MAKE NO PARTNERS WITH GOD", participating in Christmas is an accepting to god has a son, or he is god.
for Christians around here, please be open minded and understandable when I say, all I could tell you guys for 'Christmas' is....
HAVE A NICE HOLIDAY.
and may unlimited numbers of people convert and keep converting to islam ^_^
CAUSE ISLAM RULES!