10. Dungeon Fighter Online (PC, 2005) — $4 billion
This Korean online beat-em-up game never really caught on in America. But in South Korea, it's popular enough to still be played competitively.
9. Donkey Kong (Arcade/NES/Coleco, 1981) — $4.4 billion
Nintendo's Donkey Kong was Mario's first appearance (he was called Jumpman), and still one of his biggest hits.
8. Wii Fit (Wii, 2007) — $5 billion
This marquee game on Nintendo's Wii console had people exercising in their living rooms.
7. Lineage series (PC, 1998) — $5.7 billion
Another online RPG hailing from South Korea, this series developed by NCSoft is played by as many as 14 million users, making its money from optional in-game purchases.
6. Wii Sports (Wii, 2006) — $6 billion
Wii Sports was packaged with the original Nintendo Wii console, making it synonymous with the system and its motion-tracking controllers.
5. CrossFire (PC, 2007) — $6.8 billion
This free-to-play tactical online shooter hails from Korean developer StyleGate, and it has more than 50 million players from around the world.
4. World of Warcraft (PC, 2004) — $8.5 billion
This massively multiplayer online game lets you play out characters from Blizzard's Warcraft universe. It's the most lucrative online game ever and made Blizzard a household name and a billion-dollar company.
3. Street Fighter II (Arcade/SNES/Genesis, 1991) — $10.6 billion
This Capcom fighting game would go on to spawn a massive franchise, with "Street Fighter V" one of the most anticipated releases of 2016.
2. Pac-Man (Arcade/consoles/mobile/PC, 1980) — $12.8 billion
Pac-Man still gets around: His new game, Pac-Man 256, was developed by the same team behind Crossy Road, and he made a guest appearance in last year's Super Smash Bros. for Wii U and 3DS.
1. Space Invaders (Arcade/Atari 2600) — $13.9 billion
Taito's Space Invaders wasn't the first video game, but it became a global phenomenon. Urban legend says that it caused a coin shortage in Japan when it first launched. To this day, these little aliens are pop culture icons.