Some people have a "natural alarm clock" allowing them to wake up when they want. This is actually caused by a burst of the stress hormone adrenocorticotropin.
15
Cows can sleep standing up, but they can only dream lying down.
745
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
You can reschedule your sleeping pattern by not eating 12-16 hours before you want to be awake. Upon eating after this time period, your internal clock will reset to a new day, with the time of your first meal being interpreted as "morning".
11
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
The strangers in your dreams are actually people that you've seen in real life.
50