So I was out to lunch when Gretchen called to let me know that the power had dropped briefly and that when it came back up, the Internet connection was down. That proved to still be the case when I got back, so I went down to the basement and tried to power up the cable modem, which was sincerely off.
No power to the modem. And no power to the power strip either.
Unplug the power strips from the outlet, reset the GFCI switch, plug the power strips back in. Eureka! Power up the modem.
Now, let's check connectivity once everything's fired up. ESPN, yes. LiveJournal and Google, no.
Ok, clear the DNS cache on the studio computer.
And now everything works here again.
Back upstairs to the office to get everything working there.