So how do you deal with your atheism around the holidays

[drfuzzy]

My family is religious and every Christmas Eve we have our entire family over. My sister and my other sisters family of 3 kids and her husband and my other two brothers. We tend to have a nice dinner of the best clam chowder ever. We then go and each open one present each that's under the tree. However, before this my Dad will always read that Christmas story in Luke 2..I think that's where it is. And the last 2 years I just think in my head "Wow, this all sounds like such bullshit". lol Of course I don't say that, but you get what I mean. 

ALSO: Why did Christianity hijack Christmas and claim it as their own holiday? I've read that it was originally a Pagan holiday.

The Roman Saturnalia, as well as winter solstice celebrations, existed throughout the world.  Somebody decided that Jesus' bday needed celebrating, and decided that Saturnalia (which meant all sorts of celebrating that was decidedly NON-xtian!) would be a good day to spend in church.  It evolved from there.  
Jeremiah 10: 3-4 even advises the Jews to NOT cut down trees and decorate them.   That was between 626 and 527BC.  Solstice celebrations have been in existence a long time, and the xmas tree predates xtianity by at least 500 years.