Our wider family celebrates Thanksgiving in September as everyone is available for a leisurely day without scheduling conflicts. We treat Christmas as "Thanksgiving Part 2" with minor gift giving, but make a big deal about gifts for individual birthdays, as this feels more like a unique celebration.
Better to make a calender that best suits your needs.
Here in the Blue Ridge Mountains, there is something in the first week of January called "Breaking Up Christmas" or "Old Christmas," before the calendar tweakings, which is actually the end of "The 12 Days of Christmas" of yore. It reflects the Scots-Irish-Anglo traditions that have lingered among Appalachian Americans since the 1600s. Since I work at home, and don't have face time with my DC colleagues on a daily basis - and thus, their Christmas party -- I actually look forward to the "Breakin' Up Christmas" party in early January as a suitable substitute, and I don't have to put up with bosses! You just bring a dish, pull out the fiddle, rosin up the bow and sneak a beverage in your car.