Growing up, we'd go to our dad's house late afternoon on Christmas Eve, and stay over. We'd then go to my mom's late morning Christmas day, after breakfast and gifts with my dad. It got more complex when mom remarried, because the custody agreement for my stepsister involved constant switching back and forth. So the years that she was with my stepdad for Christmas Eve, we had to be back to mom's by about 10 am, so the great switch could happen around noon for her.
Now that we're adults, my sister lives several hours away (and can't drive home until Christmas day), and I'm married, Christmas is the most dreaded holiday of the year. We do Christmas day breakfast at my in-laws', go to my mom's midday in time for my sister to get there, and then we go to dad's that evening, or first thing the next morning, depending on when my sister gets into town. We do a dinner at dad's that involves EVERYONE (mom and stepdad included), but the gift exchange is typically just him and us.