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Yohoho! Puzzle Pirates is an addicting 2D MMOPG (MMO Puzzle Game) from Three Rings Designs. The game offers both free game play, and pay options. In addition, it offers International Seas (Servers) and is available for Windows, Mac, and Linux. Finally, the game offers full-screen and window gameplay.

Cube is an abstract sci-fi FPS game for the PC from 2002

Bang! Howdy is a 3D online strategy game, in a steam-powered wild west world, from Three Rings Designs. It is available for Windows, Mac, and Linux; and offers full-screen and window gameplay.

Second Life is an online virtual world developed by Linden Lab which was launched on June 23, 2003. A number of free client programs called Viewers enable Second Life users, called Residents, to interact with each other through avatars. Residents can explore the world (known as the grid), meet other residents, socialize, participate in individual and group activities, and create and trade virtual property and services with one another. Second Life is intended for people aged 13 and over, and as of 2011 has more than 20 million registered user accounts.

Vanguard: SOH is the MMORPG from Sigil Online. Unfortunately it is no longer online.

Hero Online is a completely free MMORPG. Free to play, and free to download

Project I.G.I.: I'm Going In (released in Europe as simply Project I.G.I.) is a tactical first-person shooter developed by Innerloop Studios and released on December 15, 2000 by Eidos Interactive. It is one of the first computer games to feature realistic weaponry and tactical combat situations.

Dark Reign 2 is an RTS from Pandemic Studios and Activision. The game takes place in the earth's future, where two factions, the JDA and Sprawlers, are fighting a perpetual war that is gradually destroying the earth. Dark Reign 2 features a 3D engine, 2 campaigns, and fairly standard RTS gameplay.

The Matrix Online is an MMORPG set in the Matrix universe. The game takes place after the third film. In this continuing future world, Morpheus as died, though the "machines" are not the cause and the truce is still in place.

Eve Online is a video game by CCP Games. It is a player-driven, persistent-world MMORPG set in a science fiction space setting. Characters pilot customizable ships through a galaxy of over 7,500 star systems. Most star systems are connected to one or more other star systems by means of stargates. The star systems can contain moons, planets, stations, wormholes, asteroid belts and complexes.