I tend to sleep from 5am - 10am and take a 3 hour nap during the day, say 1pm - 4pm. It's a bit degenerate but I work from home and can do this. The advantages

I tend to sleep from 5am - 10am and take a 3 hour nap during the day, say 1pm - 4pm. It's a bit degenerate but I work from home and can do this. The advantages are I fulfill all my night-owl hacking needs and have a good social life. And I can make any morning meetings by adjusting my first sleep to 4am - 8am. Apparently before the invention of the light bulb, most people divided their sleep into two sections. The details are sketchy but there's widespread reference of "second sleep" throughout history. I think it was the sort of thing they went to bed at 9pm - 1am and then 4am - 8am.