It nevers fails, every week, around 1-2pm on a Sunday. For some unexplainable reason, an overpowering drowsiness steps in, and I must sacrifice 2-3 hours of my time to sleep.
it's not a normal sleep either, it's the kind of sleepm that's very hard to break. You wake up it's 4pm, and think "There's some stuff I have to do," but by 5pm you're still happily sleeping.
Only happens when I'm at home though (which is most Sundays), and not just to me. Every member of the household seems to take a siesta on Sundays.