Why Mathematicians Now Care About Their Hat Color. “It takes a
particularly clever puzzle to stump a
mind accustomed to performing mental
gymnastics.

So it’s no ordinary puzzle that’s spreading
through networks of mathematicians like a
juicy bit of gossip. Known as the hat
problem in its most popular incarnation, this
seemingly simple puzzle is consuming brain
cycles at universities and research labs
across the country and has become a
vibrant topic of discussion on the Internet.” New York Times