I'm the most Kkkrackkkers of Amerikkkans so my tradition is just getting drunk off mulled wine and re-watching bad holiday movies with relatives I only kinda like.
I'm sometimes a little jealous of people who have weirder shit going on, like gremlins who slam doors and steal sausages or shitting Christmas logs. We need to bring back weird ass half-pagan shit.
Nothing particularly weird comes to mind--only thing notable is that it's common in Latin America to stay up until midnight on Christmas Eve to open presents.
Not my culture, but it tickles me that where Christmas is associated with family in most of the world, in Japan (where only ~1% of the population is Christian) it's associated with couples. More pointedly, there's a common pun on the word for Christmas Eve (聖夜 seiya, lit. "holy night") which swaps the character for "holy" with the homophonous 性 (sei, "sex") because it's the #1 night for couples to bang--even more so than Valentine's Day.
Japan is the weirdest place on earth.
Most of it is inflicted on them by the Dutch and Americans.