The map on Bungie.net is here:
Fence Fortress

Recommended gametypes:
Team Slayer/FFA Slayer
Team SWAT/FFA SWAT
Single/Multi-Flag CTF
All MLG Variants
(All gametypes available)
(All recommendations for 2-12 players)

This is... well... another foundry map. But it's awesome!! Seriously, this one is actually worth it.

It is a medium sized (2-12) symmetrical square map made largely from fence walls and boxes. This means you can shoot through them, but you cant throw grenades or shoot rockets through them. This makes for some very interesting gameplay, especially with the shield doors on each side.

I have spent time placing weapons, spawn points and equipment, as well as testing this map, so it plays seamlessly!

It feels like a Halo 2 map, but plays smoothly like Halo 3!

There is a sword in the middle on the top level, grenades just below it, and a rocket launcher on the floor below it. There are 2 fence towers that are high enough to snipe from, but accesible enough to take down someone on it. There is also a unique fence room built into the middle level of the towers; you can shoot through it, but the only way up is a grav lift in front of it, and the only way out is the same way you came in. Great to hide in, but bad to get ambushed in.

There is a mancannon in the middle on one side, that (depending on how you jump in it, of course) shoots you directly over the sword, to the sword, or directly through the middle where the plasma grenades are.

Being symmetrical, this is a perfectionist-grade map, although there are a few non-symmetrical elements, for the sake of gameplay; i.e., there are 2 grav lifts and 2 walkways that are diagonally symmetrical (1 on each side), but those are the only non-symmetrical pieces on the map, including weapon placement and spawn points. These grav lifts/walkways are clearly seen in the screenshots with the center structure.

Best of all, all gametypes are available!
This is also a fantastic map for SWAT.

Screenshots:
Overview 1

Overview 2

Sideview 1

Sideview 2

Center Structure

Mancannon through center structure

Flag, Shotgun, and Carbine

Tower view 1

Tower view 2

Tower room

Rocket Launcher

Just download, rate, tell me what you think- don't miss this map!