The role-playing game Ryzom takes place in the year 2531 on planet Atys.
Unlike other planets, Atys is one enormous tree, large enough to sustain an atmosphere and multiple ecosystems on its surface and within its immense underground caves created by large networks of branches and roots.
Four distinct humanoid races, or 'homins', came to exist on Atys hundreds of years prior to the game's current timeline (although it is not specified how or why!) These races developed into separate and fairly isolated societies, inside their own favored ecosystem. Interacting benevolently with all four homin cultures, but hostile towards each other, were two far more advanced races: the Kami, the legendary magical spirits of the earth, and the Karavan, the techno warriors from outer space. The Kami are depicted as elusive, chaotic, playful, and highly protective of Atys, while the Karavan are more secretive and have never been shown outside their protective suits or far from their machinery.
In the game year 2481, the homin races were nearly exterminated when the hostile and horrific mutated insect-like Kitins were accidentally released from their home deep within Atys' roots. The surviving homin refugees began working together in 2485 to rebuild a single, mixed society in relatively remote areas. Soon after that came the additional threat of the 'Goo', a spreading infestation that renders areas uninhabitable and drives wildlife mad with rage.
CPU: 1 GHz (x86-compatible)
RAM: 512 MB
GPU: OpenGL 1.2 compatible with 64 MB VRAM
HDD: ~7 GB
the engine (ryzom-core) is very awesome, this is the first game a know to build a living environment with such detail without the need of having an überclocked cpu and video card to play.
The community is very mature and helpful, altough there are exceptions, as in all.
edit: I forgot to say that, although I can play it even in an old PC with an nvidia MX4000 128RAM, the game knows how to take advantages from newer cards, as my GF8400GS on laptop.
the game also create a secure and renovable api for each char in an account to access ingame content, as forums (even available from a window ingame), char skills, inventory, etc.
beside the good gameplay and tons of possibilities and features of the game, it's very handy and comfortable to play (api+macros+customizable keys+shortcuts, etc)
Actually it's free to a level limit now. No more time limits, no more 20 days limit. There is now only a level limit of level 125, where you can still play but get no more experience. Details:
http://forums.ryzom.com/showthread.php?t=35224