My dad is a retired Air Force sergeant, and when I was a kid we were usually far away from extended family. Thanksgiving was always a time when my parents invited all the single guys who worked with and for my dad over for a big dinner. It was always appreciated and we always had a great time. When I grew up and also entered into a military lifestyle, I did the same, and to this day still look around and try to collect any 'strays' who may not have family to celebrate with. It is always a jolly group.
Christmas was always interesting in that we kept up my parents' French-Canadian heritage. The adults in any group would hit midnight mass (usually feeling no pain). The adult left behind to watch the kids would bring out any gifts from "santa". When everyone got back from mass, the children were wakened and we opened gifts. There was tourtiere and beets and lots of libations, egg nog (spiked for adults, plain for kids). we'd be up eating and drinking and tinkering with new stuff until the sun was almost ready to come up, then sleep in very late. Anyone foolish enough to be awake early got a slice of tourtiere for breakfast, and as soon as all were up, preparations for a huge dinner were underway.