It was C&W in our case - back in 2006 they had a datacentre in Leeds fed from two power stations being used to house our new Exchange & File server farm.
Mains failed one weekend and when the UPS tried to kick in it blew, took down not only all the client machines (ours included), but they were running the whole control room off the same UPS system! Can anyone say Single Point of Failure. They only told us Monday morning when the complaints about lack of emails flooded in. Whoops, sorry, didn't think you needed to know.
That was a short while after we'd had a project planning meeting with them when one of their reps stood up to talk and immediately knocked a cup of coffee into my mate's new laptop. You couldn't make it up...