Feeling groggy after your nap? It's not just you.

SLEEP
The many weird and wonderful ways animals manage to catch some z's.
There are few things more unpleasant than waking up in the middle of the night covered in sweat. We tested some sheets that promise to keep you cool and dry.
Forget sheep—counting happy little trees can help you fall asleep, too.
The new study could change the way we think about sleep debt.