As far as I know, the NFL has never had a power outage until the past year where they had 3:
Tonight at San Diego
In all 3 cases, the 49ers were playing. What are the odds of that (I think it is 1 in 4096)? It seems like the 49ers have some strange curse. If I am the power company/stadium manager, I start checking my electrical system twice before they come to play. I hope the 49ers new stadium has a backup system in place.