RuneScape

"RuneScape is a Java-based MMORPG operated by Jagex Ltd. With over nine million active free players and more than 850,000 paying members, RuneScape is rated among the most popular online games in the world. RuneScape offers both free and subscription content and is designed to be accessible from any location with an Internet connection and to run in an ordinary web browser without straining system resources.

RuneScape takes place in the fantasy-themed realm of Gielinor, which is divided into several different kingdoms, regions, and areas. Players can travel throughout the gaming world on foot, by using magical teleportation spells or devices, or mechanical means of transportation. Each region offers different types of monsters, materials, and quests to challenge players.

Players are shown on the screen as customisable avatars. They set their own goals and objectives, deciding which of the available activities to pursue. There is no linear path that must be followed. Players can engage in combat with other players or with monsters, complete quests, or increase their experience in any of the available skills. Players interact with each other through trading, chatting, or playing combative or cooperative mini-games."

http://www.runescape.com/