I get home, and the monitor on my Linux system is wigging out. This is not good, as this is the third monitor on the system since 2009.
Also, the computer is quite loud, louder than normal, which means, it's hotter than normal, which isn't good. I never did find out what was constantly running, but I did isolate the issue with the monitor—it's not the monitor. That's the good news. It's the video card.
Lovely! I cooked the video card to death!
Sigh.
And in the process of troubleshooting all this, the shelf the computer was sitting on (attached to the computer desk) broke. Or rather, the caster beneath the shelf wrenched itself free, causing the shelf to collapse under the weight of the computer.
Double sigh.
At least the computer itself is fine. The shelf is in the process of being repaired (should be done by tomorrow) but the replacement video card won't get here for another week or so.