Play-Doh

This legendary toy was originally manufactured as a wallpaper cleaner in the 1930s and is made of flour, water, salt, boric acid and mineral oil. After Joseph and Noah McVicker realized that the cleaner could be used as modeling clay, they tested the product in Cincinnati-area schools. Play-Doh's sales reached nearly $3 million in 1958 and, in 1965, General Mills bought all rights to it, allowing Joseph to retire as a millionaire. Later in life, he decided to become a minister and attended Harvard Divinity School.