[ALUG] detecting power failure

Hello ALUG, Does anyone know if there will be a log entry somewhere on my Debian system (or anything else) which will tell me if it suffered a power failure over the weekend? I've just noticed that the web and database servers on my workstation (I use them for testing code) were running when I came in this morning and I'm sure I stopped them both on Friday. Everything else about the machine is normal. Cheers, Richard