Battle for Wesnoth
(http://www.wesnoth.org/images/sshots/wesnoth-1.3.13-2.jpg)
(http://www.wesnoth.org/images/sshots/wesnoth-1.2-f.jpg)
A fantasy turn-based strategy game. Much like Advance Wars or Fire Emblem. Multiple campaigns, multiplayer, and level/campaign editor.
Website (http://www.wesnoth.org/)
Download (Windows) (http://sourceforge.net/projects/wesnoth/files/wesnoth/wesnoth-1.6.5-win32.exe/download)