A recent fad amongst geeks has been the bi-modal sleep pattern — breaking up sleep into multiple segments in an attempt to maximize the amount of time awake that one can devote to coding or writing or running in place or whatever else one deems to be productive and useful.
Back in Europe during the Middle Ages, people would sleep in two
shifts, with a period of wakefulness in between where they might take
care of chores, write, gossip with neighbors or have sex. They called
these periods First Sleep and Second Sleep.
I mean sure, you always hear about Leonardo da Vinci and Thomas Edison and other oddball geniuses that slept in 4 hour stints, but this is the first I'd heard that it was a common practice.