I got a 3am call because of some problem when a new version went out to production. It turned out to be some code using an external hostname that was invisible to the internal host. I wasn't involved in figuring out the problem, because I was looking at the pieces that I had worked on. When it was figured out, I went back to sleep. These problems keep turning up because there are no distinct internal and external hostnames in the testing and development environments, and anyone new to the project hasn't gotten lots of these late-night calls.