Verdacia, The Great Green Valley
The Verdacia campaign is designed for quick episodic sessions. Players are encouraged to make a group of characters, choosing one for each adventure- to keep things fresh and interesting. Verdacia as a setting is usable with any game system, but is written with primarily Dungeons and Dragons in mind.
To get a feel for where the world is now, check out the article about the Great Civil War. This is a good overview of how Verdacia got to where it is now, and gives some potential adventure/background hooks.
To start making a character, check out the Races of Verdacia, as they are slightly atypical of general fantasy settings.
Those interested in playing wizards, or other magical characters should read the page about Arcane Magic. Many wizards are shunned in Verdacian society, but all are free to play as one.
Finally, all player characters are part of the Three Fingers Mercenary Band, see the attached article for basic history and rules of the band.