In the early 1970s mathematician Donald Knuth spent a sabbatical with his wife in Norway. The time was meant to be spent relaxing. Yet one night he woke up his partner in a state of agitation. He ...

If you've got the time, we've got the riddle. And it's time for a riddle about time: How many numbers are on a clock? It begins with the simplest of questions that, nevertheless, has no simple answer.

The shutdown is the result of weeks of disagreements between Republicans and Democrats in Washington over funding the government. Here's the back story: ...