It is the one day over the Christmas holidays where you are entitled to uninterrupted X-Box entertainment without the apprehension of having to switch it off.
This remarkable day occurs either on Boxing Day or on some other agreed day with your spouse.
Whilst it is lovely spending time with family, this is an effective pragmatic settlement that helps to soften the unpleasant experience of unwillingly enduring dreary Christmas TV, imposed through common family demand.
"I hear you are not spending Christmas at home this year, is there any chance you could jump online for some Special Ops?"
"No, but I do have an X-Boxing day agreement. Unfortunately I am ill-fated to be in an unfamiliar habitat during Christmas, but Knowing X-Boxing day is nearing whilst I respectfully give my support to another’s customary routine, is especially reassuring."