"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." If you love solving riddles, unlocking mysteries, or completing any other brain-boosting activity, puzzle ...

If you told your kids they were going to spend the day working on problem-solving methods like improvisation, trial and error, and logic and reasoning, what do you think their response would be?

What's the origin of the name China? Why did the Mayan people base their math system on the number 20 and not 10? And who first calculated the Earth's circumference? How did he do it? Maybe you can't ...