Eight Inventions That Came Before It

By today's standards, "Pong" seems ridiculously simple. Yet the game's debut 40 years ago this month is often described as the birth of the video game industry, one in which a single title can now top $1 billion in sales. While Atari's "Pong" was the first major commercial hit, there were games that came before it, such as "Tennis for Two" and "Spacewar!" Here's a look at some of those earlier inventions.