Slinky
Invented in 1943 by naval engineer Richard James and first marketed in Philadelphia in 1945, the slinky was destined for greatness that has since taken it into space on the Shuttle, to war in Vietnam, and into thousands of physics labs in schools across the world.
All you need is a slinky and a set of stairs, and a whole afternoon slips by. For sheer exuberant slinkability, there is only one original slinky.
