I made a scooter-trip out to Wal-Mart, that paradise of shopping (er, what I mean to say is, "the only place that's open at 1am for paranoid bug-combatants") and bought a couple gallons of anti-spider poison. Got home and poured one gallon along the house's walls and foundation outside, then squirted half the second gallon along bug-friendly pathways up the walls, then went inside and squirted all along the bases of the walls upstairs and down, in the attic-room, plus in the cupboards and fireplace and furnace area.
Then a shower, as I didn't really gear up properly and my nose was running something fierce. By now the liquid has dried up, it's damned late, and I feel confident that nothing can survive breaking into the house. To bed!
Here's wishing you no spiders,