Video games aren't just for kids. In fact, they are big business. According to the industry-tracking NPD Group, sales of games and consoles totaled more than $13 billion in 2012. With the recent introductions of the PlayStation 4 and the Xbox One, Sony and Microsoft are just the latest in a long line of companies competing for a piece of the pie. Take a look back at the consoles of the past.

Magnavox Odyssey
Release: 1972.
Units sold: 330,000.
Of note: Used plastic screen overlays for many games to simulate graphics the unit was not powerful enough to display.
Top games: Had 27 total.

Atari Pong
Release: 1975.
Units sold: 150,000.
Of note: Settled out of court for patent infringement over the game's similarities to Magnavox's "Tennis" game for the Odyssey.
Top game: "Pong."

Atari 2600
Release: 1977.
Units sold: 28 million.
Of note: Was the first highly succesful game console. Credited with popularizing interchangeable game cartridges.
Top game: "Pac-Man."

Intellivision
Release: 1979.
Units sold: 3 million.
Of note: Was the first console to feature downloadable games – but had no storage device to save them.
Top game: "Las Vegas Poker & Blackjack."

ColecoVision
Release: 1982.
Units sold: 1 million.
Of note: Offered near-arcade-quality graphics, and an adapter allowed it to play the entire Atari 2600 game catalog.
Top game: "Donkey Kong."

Nintendo Entertainment System
Release: 1985.
Units sold: 62 million.
Of note: Debuted some of the most popular franchises, including "Legend of Zelda" and "Final Fantasy."
Top game: "Super Mario Bros."

Sega Master System
Release: 1986.
Units sold: 15 million.
Of note: Was once distributed in the United States by Minnetonka-based toy maker Tonka.
Top game: "Alex Kidd in Miracle World."