Things are making much more sense to me now seeing this post. I have host-tracker.com tracking two different areas of my personal site because they're driven by different databases. When I checked my email this morning, there were all kinds of error reports from host-tracker about one of those areas, the one whose database is on stimpy (the error message host-tracker gave me was "Http error:Http_client.No_reply") but not the other, which was baffling me because if the web server was down I should've seen errors for the other part of the site, too.
Anyway, FWIW, Host-tracker claims the total downtime was about an hour and 15 minutes. The "operation restored" message from them was timestamped 7:57 AM Eastern time.