During a blackout in Los Angeles (apparently caused by some dorky engineer cutting the wrong wire), DreamHost suffered from a faulty backup system. Generators that should've kept everything running smoothly contrived to fail, and the DreamHost team were required to evacuate their datacenter for a while.
Once power was restored, the guys carefully brought the system back online and ironed out the inevitable secondary issues in short order. The whole time, DreamHost customers were kept informed by the off-site status page. As soon as power was restored, an explanation of what was happening was given on the DreamHost Blog.
Once again the transparency of the company, and the thorough willingness to do the best they can, has made me pleased I chose this webhost. I can thoroughly recommend DreamHost webhosting to anyone who is serious about their websites.