The oldest building would be the cathedral built between 1628 and 1633 although the city walls were built between 1613-1618 and are still standing and complete

For shooting games we played "hot potatoes". Basically once you got a kill you had to get to the person you killed and take their weapon to make your next kill.

Sounds bland in text but really fun when you get going with it.

Signal messenger has a note to self function that can be opened on the phone and windows that will do text and small files

I would look into grinding and sanding it flat and a resin coating to seal the surface. There are YouTube tutorials to DIY it if you are price conscious

You'll want to avoid pornlemmy.com and lemmynsfw.com . Lots of nudity and unwholesome behaviour depicted there

Edited for spelling

I like the idea. I suspect it would make moderation a challenge but it sounds pretty useful