This year, mostly GURPS. It’s such a delightfully comprehensive TTRPG. If you can think of it, you can do it, and odds are that unless you’re thinking of something really out there, it’s explicitly outlined in one of the source books. Even if it is really out there, you can probably find several forum posts outlining several ways to run the mechanics.
It’s not a perfect reality simulator, but it’s good enough for me.
I predict that once robotics and AI advanced beyond some particular threshold, human-on-human relationships will be seen as strange and needlessly fetishistic. Who would want some grimey partner with their own needs when you can generate an infinitely moldable soulmate?
On a serious note, yes Christmas was placed where it was in order to coincide with Saturnalia, the Roman winter solstice festival. This was an attempt by Constantine, the emperor who legalized Christianity in Rome, to transition the Romans to Christianity more easily.
Primer and The Man from Earth are two of my all time favorite films. Production value is nice and all, but an interesting idea explored well wins every time for me.