Scorched 3D is a game based loosely (or actually quite heavily now) on the classic DOS game Scorched Earth "The Mother Of All Games". Scorched 3D adds amongst other new features a 3D island environment and LAN and internet play. Scorched 3D is totally free and is available for both Microsoft Windows and Unix (Linux, FreeBSD, Mac OS X, Solaris etc.) operating systems.

If you feel that your productivity is excessive, then download scorched3d and get your cross platform game on. Its alot of fun, especially apocalypse mode. They took the old school weapons set and expanded on it. Takes a minute to get used to the 3dness, but once you do you will have a blast hitting tanks across the screen on the first shot. Until you can pull that: smoke tracers are your friends. Followed immediately by the MOAB.

It takes about a minute sometimes to get back to your turn on a 10 player game, so you can actually get some work done while playing if you have two monitors.