[SypheDMar]

http://www.indiegogo.com/projects/support-0-a-d-an-open-source-strategy-game

In short, 0 A.D. is a free, open-source, cross-platform, real-time strategy game of ancient warfare.

To break it down (and get rid of a lot of hyphens!), the game is similar to the classic games in the Age of Empires series and is completely free to download and play.

0 A.D. is not only completely gratis, but its codebase is freely available under the GPL and its art and music are licensed under CC BY-SA. It's free to distribute and mod. This means there is no DRM. And, above all, 0 A.D. sets an important precedent for software freedom in computer games. More on that later.

So I've been following this project for a long time because of the thought of a high quality open source RTS game didn't seem feasible up until this game appeared. They're starting a crowdfunding campaign using Indiegogo. They've had Alpha versions that are released with regularity if that helps their credibility. Best of all, it's a 501 (c)3 for those who care about that stuff.

[Zacam]

Moved from GenDisc to Gaming Discussion.

Enjoy.

[Mongoose]

Age of Empires kicked ass, so hopefully this will live up to it.

[Luis Dias]

This is exactly what I want games to become. People pay up games upfront if they want it to become reality, game becomes free and open source for everyone to adapt and use however they like. I don't think this kind of economics will outpace and outrun private IP development for a long time, but the mere idea is fascinating and appealling!

[SypheDMar]

Regardless whether they succeed, they will still make the game for free. It'll just take much longer.

But I liked their concept a lot too. I don't know many high quality open source games are available to the public for free (besides the many FPSes)