www.wesnoth.org
It's a free TBS game (GNU), very similer to advanced wars, with alot of content. It also has alot of player created content to download. It also has a pretty good multiplayer.
The game is a stragegy game that takes place in a "lord of the rings" type world, with orcs, dwarves, elves, and many other different races. The different races play differently, making it interesting to discover the new units, and how they work.
The game has all kinds of different difficulty levels, ranging from a guided mode, to an insanely difficult mode, and everything inbetween.
I definitely would recomend downloading it.
