I've put together 14 high-quality original podsafe instrumental tunes from my Penmachine Podcast into a CD album you can buy. It also includes a bonus data DVD with a bunch of cool stuff that isn't on this website. Find out more...
You will start to feel noticeably tired at 15:00 and you will feel most tired at 16:00.
That's bang on for me. If I'm at home with the kids on a typical day, I could easily fall asleep at 4:00 in the afternoon. An hour later, even I have not napped (which I usually don't), I'm wide awake again.
Siesta is a good idea, rarely applied in North America.