RuneScape

RuneScape is a fantasy massively multiplayer online role-playing game (MMORPG) released in 2001 by Jagex Ltd. It is a graphical browser game implemented on the client-side in Java, and incorporates 3D rendering. The game has approximately 10 million active accounts per month,[1] and is recognised by the Guinness World Records as the world's most popular free MMORPG.[2]
RuneScape takes place in the world of Gielinor, a medieval fantasy realm divided into several different kingdoms, regions, and cities.[3][4] Players can travel throughout Gielinor on foot, by using magical teleportation spells and devices, and many other methods such as charter ships.[5] Each region offers different types of monsters, resources, and quests to challenge players. The game's fictional universe has also been explored through a tie-in video game, Armies of Gielinor,[6] and a novel, Betrayal at Falador.[7]

Players are represented in the game as customizable avatars. RuneScape does not follow a linear storyline; players set their own goals and objectives. Players can fight NPC monsters, complete quests, or increase their experience in any of the available skills.[8] Players interact with each other through trading, chatting, or by participating in both combative and cooperative minigames and activities.

Source: http://en.wikipedia.org/wiki/RuneScape