BZFlag - LQWiki

From LQWiki

BZFlag is a very popular open-source multiplayer tank battle game. A multitude of servers around the world provide many environments to play in. It is very addictive; some people even complain of not being able to part with it.

Setting up BZFlag is usually an easy task; most distributions have it available via their package managers. Development is quite active however and if you decide the game is good for you, keeping up with development is a must (every once in a while the protocol changes, making older clients incompatible and obsolete).

Some folks (including me) want to play BZFlag with a joystick; not to fear! The next version, at the time of this writing 1.12, will support SDL and many joysticks are natively supported via that.

If you have a slow graphics card it's a good idea to turn off smoothing (which makes the lines on the radar anti-aliased), decrease the detail, etc.

There is a multitude of cool patches you can apply to the source to enable nice things like tabbed message panels, and it is possible to enhance the textures the game uses or create your own.