The house is back up to code. In replacing Missy's ceiling fan a couple days ago I got a shock...with the breaker open. And found upon further review that the upstairs circuit has a hot ground. Or something. Anyway, I couldn't find anything obviously crossed so I called in a professional, who spent the better part of a day and a half crawling through the attic, removing fixtures, and sorting wires until he found the source of the problem, which was a ground wire in a hall outlet bent over and touching a neutral screw. Two circuits upstairs with a common ground then had electrons going where they weren't supposed to. But now it's fixed, so we won't burn the house down or anything like that.