Probably because of the burden on the system. 98* and EVERYBODY had their AC on. I expect it to happen again in the next few days.
Didn't surprise me much when it when out, but Tasha, the STLMedia Watch Dog was troubled. She had just come in from the yard when the AC went South and Miss Dog 2010 sat in front of the TV, looking, wondering, why there was no image.
Tasha walked around sniffing at the fans and the AC vents and just gave it up. Nap time. The power came back about an hour later.