Set in antiquity and designed with historical accuracy as a priority, 0 A.D. is a real-time strategy game that supports Linux, Windows and OS X. The developers, Wildfire Games, originally intended to distribute it as freeware, but decided to open-source the code last summer in hopes that it would speed the development process.
The game is not yet really playable, but it runs. Here are some screenshots:
And here are some more interesting shots courtesy of the game's Wikipedia article (it was not playable enough on my computer to get any very exciting scenes):
Why it's great0 A.D. is probably the only open-source RTS game besides Glest that attempts to bring to Linux users a gaming experience otherwise available only on Windows (or through wine, sometimes). Other strategy games for Linux exist, some of them decent enough to provide a few hours' entertainment, but they're mostly half-baked and lack the professional quality of their commercially developed betters, especially when it comes to art and gameplay.
That's no surprise, since the free-software community is short on the kind of talent required to create good games. Coders are available in abundance, but finding experienced artists, designers and writers willing to contribute to open-source projects can be difficult, especially when cash is tight.
Despite these odds, 0 A.D. has clearly managed to assemble some impressive non-coding talent, as the artwork above attests to. If the game receives the necessary support from the community to put out a successful product, it will set an important precedent demonstrating that quality games can be developed on the open-source model. It will also send a message to vendors that Linux users care about games, which may help expand the dismal range of offerings currently available for Ubuntu.
Appendix: installing 0 A.D. on UbuntuThe game is still highly unstable, but packages are available from getdeb. To install the game from that repository, just type:
Note that the getdeb packages were built in July, and are missing all of the improvements implemented since then.
The truly adventurous can try compiling from source using the latest subversion code. The instructions in this Ubuntu Forums post worked for me on 64-bit Jaunty. Unfortunately, although the code compiled without a problem and the application launched, it crashed when I tried to start a new single-player game. But I may simply have checked out a bad svn snapshot.