Last month, our very own Stacy (who just survived a freaky accident involving a downed power line - glad you're ok, Stacy!) wrote a very neat post over at mental_floss about the background stories of 10 classic toys.
Take, for instance, Slinky:
Slinky was invented by Naval engineer Richard James. He knocked a spring off of a shelf when he was working to develop springs that could keep ship instruments stable in choppy waters. The spring did what a Slinky does… it stepped down to a stack of books, then to the table, and then to the floor, where it righted itself into a cylinder. James knew it would be a great toy, and tests by neighborhood kids proved him right.