Here are some links worth testing, if you want some cool open source strategy games for Linux – and Windows:
A free Civilization Clone: Freeciv – The best ever!
A free Colonization Clone: Freecol
A free Master of Orion Clone: Free Orion.
Remember the boardgame “Carcassonne”? Here’s Cassiopeia.
The Open Source Racing Simulation: Torcs.
Remember “Die Siedler”? Widelands.
Globulation 2 is an innovative Real-Time Strategy (RTS) game: Globulation
Warzone 2100 is a 3D realtime strategy gamein the future, including technology, warfare and much more.
A complete Framework for “turn based space empire building games.”: Thousand Parsec (Contains a example game named Minisec)
Another Engine for and with a lot of strategy games is the Spring Engine