Install from Wildfire's PPA:
Or open the Terminal and type
sudo add-apt-repository ppa:wfg/0ad sudo apt-get update sudo apt-get install 0ad
(If you get errors about unmet dependencies, check that you have the Universe repository enabled in /etc/apt/sources.list.)
Run the game from the command-line as
or from the application menu item "Games" / "0 A.D."
Unstable version: You can try a more up-to-date but less-well-tested version from Wildfire's development snapshot PPA, which should be updated each week. Follow the instructions above but use the ppa:wfg/0ad.dev repository name.