I love being up late. Nobody asking me to do things, nobody to question how I spend my time, and my monitor performs best in the dark.
In my freshman year of college, I would stay up late working (or not working) on projects. I would also chat with people on my IM contact list, who were scattered across the Western Hemisphere. It was… nice, bidding my European friends goodnight and seeing them off to bed, and being there to say “good morning” when they woke up.
Also in my freshman year, I learned (thanks to a 7:00 a.m. public speaking class) the joys of being up before everybody else, reading the paper and working my way through my pancakes and eggs.
I also like low-light settings. One of my favorite fantasy settings (as in mental vacation fantasy, not the literary genre) is a place that’s dark overhead all the time (but clear, so that you can see the stars and moon and all), and cool and quiet like a late summer evening, properly illuminated with lamps and populated by the sorts of people that you like to hang out with around a campfire.