yeah we do - my mother's from n. europe so that always seemed to be the reason, but then as we got older we found out it's a tradition on my dad's side of the family that goes back over a 100 years - otherwise it would have been a bit unfair on the cousins
basically, the reasoning seems to be let the kids open up on Christmas eve, wear themselves out so that the adults get to sleep off the worst of it the next day.
Usually about 30+ family members sleep over at my grandparents' for the 3 days. TV banned. Food, drink, games, long walks in the country to get hungry/sober again

and a lot of general pitching in in the kitchen
it's a blast but it's wildly different from what most of my friends did
due to working overseas, haven't made it back for the last couple of years - really miss it, but we made up for it here