In 1947, the El Zarape Tortilla Factory in Los Angeles purchased a new piece of equipment that could turn out tortillas many times faster than human workers could ever duplicate. It took some time to get things right, however, and in the beginning many of the tortillas came out of the machine imperfect, usually misshapen or doubled over or torn apart.
Not wishing to waste an edible product, the company's president, Ms. Rebecca Webb Carranza, took the discarded pieces home where she cut them into conveniently-sized triangles and fried them, serving them at a get-together as a snack to be dipped or crunched alone. The result was an immediate hit, and Ms. Carranza immediately saw the commercial potential of the little snack chips.
By the early 1960's, these 'tort chips' had become the factory's primary money-maker, and were being sold up and down the length of California as an alternative to regular potato chips, and as a regional novelty food that took advantage of the region's Mexican heritage. Within the next two decades it would spread across the entire United States and become not only a popular dipping chip, but also - when a dollop of molten cheese was added - a small, portable meal suitable for sports enthusiasts (usually called nacho chips in this incarnation).
The company didn't properly patent the chip design, so anyone is free to manufacture the now-ubiquitous chips; the most popular brand, however, remains Doritos, distributed by Frito-Lay, which were first sold in 1966. But most grocery store chains sell their own brand of triangular or rounded corn chips. (And no, the original taco-flavored Doritos are not to be found anymore, anywhere: they stopped being manufactured in the late 70's.)
Ms. Carranza herself passed away at the age of 98 in 2006. She probably still misses the original taco-flavored Doritos, too.