Back when I worked 6am shifts at work I woke up at 5am every day, including my days off. This went on for a solid year or so.

It was kinda neat waking up before everyone else and getting everything done nice and early. The downside, of course, was that I was dog tired by about 9pm. But hey. xD

(It's actually when I wrote my first book. In the wee hours of the morning. )