These are harvestmen, a type of arachnid that is not a spider. In my part of the country they’re also known as daddy longlegs. We saw several of these groupings, called aggregations, along the ceiling of the porch at the cabin. While a little disturbing at first, we soon ignored them, just as they ignored us.
We often see lone harvestmen around the cabin (though rarely inside), but I can’t recall ever seeing them grouped like this.
It is a myth that these critters are venomous and/or that their fangs are too weak to break human skin. According to Wikipedia, they have neither venom glands nor fangs.
So, I live and let live, at least outside the cabin, like a good forest steward should.