There are a lot of Massive Multiplayer Online Role Playing Games out there right now. A lot of them are free and driven by advertising and in-game money. Wakfu is grid-like, turn-based free MMORPG, but has native support for Linux.
There is a lot more than your standard RPG...
Select from 15 classes consisting of ranged, melee, steam-punk, mage-like and much much more.
Utilize many abilities and skill attributes to battle multiple minions. Follow quests or just explore the land. Use an interesting take on Alchemy by harvesting animals and plants, then planting more. Join up with friends or play solo and level up your characters abilities and skills.
The possibilities are endless...
Follow my step-by-step guide on installing, configuring and optimizing Wakfu in Linux.
Download Wakfu
Go To:
http://www.wakfu.com/en/mmorpg/game/download
Click Download Wakfu
Navigate to your desktop
click Save...