Hello! This one of my CTF arena's I have built for my server and use. It has been tested and is functional.
(For use on your Bukkit Servers - requires some kind of CTF plugin.)

This map setup for Red-vs-Blue style capture the flag and the style for the map I chose is setup to mimic CTF maps from games like Unreal tournament and Quake. The map Is designed for a 4-18 players.

How the map works -
*Each team starts in a spawn area the opposite team cannot access.
*In each corner room a lamp indicates if your teams flag doors are open or closed.
*In order to get access to the other teams flag room, one has to find there way to the map center and activate the opposite teams flag door(s), opening them.
*Once the flag doors have been opened you have to make your way to there flag and retrieve it before they can close there flag doors again from the map center, locking you out.
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GOOD STUFF TO KNOW -
*If your teams flag doors are closed. you can still gain access to your own flag room through the spawn area war ethe opposite team cannot get to.
*If your in the flag room and the flag doors become locked. there is a one way exit that either team can still use to get out but not back in.
*It is wise to have some players guard the flag door levers and some guarding the actual flag.
*working as a team is a must.
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Some Other Stuff from experience -
*The maps works best with at least 3 people on each team and thats the minimal.
*The map was built to be used with the Ultimate Arena [UA] plugin for 1.6.4 bukkit. I do not recommend this plugin.
*The map works on most other CTF plugins very well.
*If your going to create a schematic of the arena to move it to another map... Please have a look at the redstone wiring under the arena first so you know ware it is and dont cut it off on accident.
*I myself have converted this map into deathmatch/pvp arena by simply changing all the red/blue wool to one color and removing the door triggers.

Additional Notes

this map could very easy be make into an infection arena as well. ive converted it myself to several other types of games arena's.