• 1. Play-Doh

    What was originally a putty-like wallpaper cleaner is now one of the most popular clay toys for children. It was created by Noah McVicker for Kutol Products, a soap company, in the 1930s.

  • 2. The Slinky

    In 1943, naval engineer Richard James accidentally knocked a mechanical spring off of a shelf and watched it “walk” across the room. He later turned the toy into the Slinky. When the toy went on sale in November 1945, it sold out its entire inventory of 400 units in 90 minutes.

  • 3. Silly Putty

    During World War II, rubber rationing caused the US government to research synthetic rubbers. The product spent years languishing in laboratory until a toy manufacturer discovered the stuff in 1949 and started selling like hotcakes.

  • 4. Post-it Notes

    The low-tack reusable adhesive was accidentally developed at 3M in 1968.

  • 5. Penicillin

    Alexander Fleming discovered penicillin on September 28, 1928 in the basement of a London hospital. A culture he had left out had developed a blue-green mould that later became penicillin.

  • 6. The Popsicle

    In 1905, at age 11, Frank Epperson left a mixture of powdered soda and water out on the porch with a stick still in the container. The next morning, he discovered the frozen mixture and called it the Epsicle. The product was formally introduced to the public in 1923.

  • 7. Chocolate Chip Cookies

    The chocolate chip cookie was accidentally invented by Ruth Wakefield at the Toll House inn in 1933. She ran out of baking chocolate for her cookies and decided to use broken-up pieces of semi-sweet chocolate instead. The chocolate did not melt uniformly, instead coming out in little chunks.