War is a plugin for Bukkit that adds PVP arenas and team deathmatch gamemodes to Minecraft servers.
Visit http://war.tommytony.com for more info, videos and links.
All official releases are at https://github.com/taoneill/war/downloads.
Development builds are available at https://cmastudios.me/cgi-bin/war.py.
tommytony started the plugin in December 2010 on hMod and has been maintaining it since with the help of contributors. Reach him at taoneill@tommytony.com.
War is licensed loosely under the MIT License (but still comes with the weird baggage of Bukkit licensing)