During World War II, chemists concerned about America's threatened rubber supply began researching synthetic substitutes and stumbled upon one of the greatest materials in toy history. A "solid liquid," the new, stretchable material was a marvel of science — and of absolutely no use to the American war effort. Dubbed "Nutty Putty," the new substance was marketed as a novelty toy by entrepreneur Peter Hodgson, who sold it packaged inside colorful plastic eggs, just in time for Easter. When a write-up appeared in the New Yorker, Hodgson received more than 250,000 orders in three days. Scientists and toymakers have been refining everyone's favorite nonrubber ever since. The year 1991 saw the introduction of glow-in-the-dark Silly Putty, while NASA learned the substance could be used to restrain objects in zero gravity, taking it aboard Apollo 8 to hold down tools.