Other Life is a cute 'old school' mmorpg in the fantasy genre. It's based on the Eternal Lands engine and inherits heavily from that game in terms of its assets and styling, but with many improvements server-side (many more planned) and superior client software.
Whilst Other Life is still in fairly heavy development and testing, it's fully playable. It's also fully free to play and, whilst there is a shop from which you can buy cosmetic and convenience items, all critical content is accessible without payment.
Although the server code for Other Life is currently closed source, the client code is freely available under a modified GPL licence and compiles under both linux and windows. The client is written in C and is under continual development by the community, something that makes the game particularly ideal for those who like to create modifications and help out with coding and development.
Website : http://www.other-life.com/