We owe a great deal of the modern world to people doggedly trying to solve a high-minded problem: how to construct an internal combustion engine or manufacture vaccines in large quantities. But a surprising amount of modernity has its roots in another kind of activity: people mucking around with magic, toys, games, and other seemingly idle pastimes. Everyone knows the old saying “necessity is the mother of invention,” but if you do a paternity test on many of the modern world’s most important ideas or institutions, you will find, invariably, that leisure and play were involved in the conception as well.