A few years ago, there was a Mensa convention in San Francisco. Mensa, of course, is an organization whose members have an IQ of 140 or higher. Several of the Mensa members were lunching at a local cafe. While dining, they discovered that their saltshaker contained pepper and their pepper shaker was full of salt. The Mensa members, being naturally inquisitive, began to question how they could they swap the contents of the two bottles without spilling any of the contents, using only the implements at hand. After all, this was clearly a job for the best minds available.

The group debated and presented ideas, and finally came up with a brilliant solution involving a napkin, a straw, and an empty saucer. They called the waitress to their table—convinced that they would dazzle her with their s…