Battle for Wesnoth - Awesome Turn-Based Strategy Game
Battle for Wesnoth is one of the most popular and played turn-based strategy (TBS) games on Linux, if not the most popular. It’s a free, open-source community-driven project which has done some amazing improvements since its initial release, in 2003. It comes with wonderful concepts for gameplay, it includes great 2D artwork and music, and more important, it can keep you playing inside a fascinating universe, either online in multiplayer battles or in single-player mode in beautiful campaigns or single-map mode versus AI.
Although I never was a truly skilled player, I always enjoyed to complete a campaign, go play on the official multiplayer server or just read the forum, which actually is a great resource of strategy tips, ideas, suggestions and debates regarding playability or improvements.