Programmers work at night because it doesn’t impose a time limit on when you have to stop working, which gives you a more relaxed approach, your brain doesn’t keep looking for distractions and a bright screen keeps you awake.

http://en.codeceo.com/why-programmers-work-at-night.html

Though I keep working at night to a minimum it sounds very familiar. It seems a bit strange but not having a deadline is great for productivity for some types of tasks.