I got a call from the person who colocates my server in his basement. He told me that his neighborhood has been without power for a half an hour, and the UPS can only hold for probably another 20 minutes. (yes, he has very nice UPS equipment) :->
It just died.
Ahh well. I'm about to go to bed anyway, and my backup MX is working fine now, so no harm done, really.
Kinda glad he told me though, I like finding out this way rather than calling him.