I've heard about Christmas truces in the American Revolutionary War, WWI, and WWII, where soldiers put down there weapons for the holiday, sometimes even meeting to exchange candy, tobacco, etc. How were these organized? Has this been a pattern throughout military history?
On the other hand, how has this played out differently? i.e. attacking the enemy when you know they won't be ready because of a religious or cultural event they were observing/honoring.