The genius of a folk melody or story is not the feeling that it's original but quite the opposite—the feeling that it has existed all along. This is the same genius at work in products like Silly Bandz that are so simple and obvious that all you can do when you first encounter them is pound yourself on the head with a rubber mallet and moan, "Why didn't I think of this? Why didn't I think of this?" In case you have been cryogenically preserved for the last year or so and were just recently...