BANG! Awake.
A few minutes before 5:00 AM I was awakened by a bang! that could have been something falling to the floor or could have been an electric discharge. I could tell which. Given the possibilities, I went looking and hoped to find something that had obviously fallen and not find something sizzling or smelling of ozone or with the "magic smoke" odor.
The good part was that I didn't find anything sizzling, didn't smell any ozone or "magic smoke" though I wasn't entirely sure of that last one. Everything seemed to be working normally. The bad part was that nothing stood out as obviously having fallen. The other bad part was that the DSL connection had gone out. Something in the basement couldn't have made a bang that sounded that close and loud, could it? Uh oh.
The stuff in the basement was working fine, except for the DSL modem which was power-cycled. The connection returned and I went back to bed for the next hour, not sleeping well due to the activity and still being unsure just what had happened.
A while later jmaynard, who is in the Atlanta area right now, was able to confirm that everything that should be running really was. The only thing that might have been out of place was a hard drive on the machine room floor, but there's a fair amount of stuff on the machine room floor. I mentioned that and after finding out just which hard drive Jay said that it had been on some shelving. That's a bit of a relief, though that the drive was able to slip and fall from where it was is a bit worrisome.