Smoked, and not in a tasty BBQ sort of way either.
Not sure what happened, but while I was sitting at my desk at work catching up on some reading, all the fans on my desktop computer suddenly spun up and the thing started sounding like it was ready to take off.
This was followed very closely by the unmistakable odour of fried electrical components.
Naturally this all happened just before I was ready to leave for the day, so I haven't had an opportunity to do any diagnostic work yet. That will have to wait until the morning. Hopefully the data on the hard drives is still intact. There's a lot of data I'd hate to lose. Scrounging enough parts to figure out what's wrong or to build another desktop could be challenging.