It is hard to imagine the hassle we all went through to reheat lunch or fill a bowl of popcorn before the advent of the microwave oven. Your beeping buddy in the kitchen owes its existence to a Raytheon ( RTN) engineer who, back in 1945, was experimenting with a device called a magnetron, a microwave -emitting tube used as part of military radar systems. As he tinkered with the device, he noticed a candy bar in his pocket melting. Suspecting the radiation was cooking his snack, the engineer set out to test the theory. In doing so, Percy Spencer discovered a revolutionary way to cook and goes down in history as the first person to make microwaved popcorn. Built in 1947, Raytheon's first take on the oven was targeted at commercial uses -- it was more than 5 feet tall and cost roughly $5,000. In 1967, Amana, a Raytheon division, began selling sub-$500 versions intended for at-home kitchen use.