Going up? was built with the ASSET game varient in mind, but I've also modified the map and supplied a link for a "non-asset" FFA map.

This map is a 6 floor tower, with a huge one-eyed monster in the center of the building. The statue (Monster), adds both cover & can be used to jump off of, making this map more than just a linear-straight path map.

The Mission...
The Asset has been captured by the brutes and is bieng held in a detention cell at the base of the tower. The ODST have covertly gained access to the building and are in the process of escorting the Asset to the rooftop for extraction.

The Brutes
I used 3 brute-types in this map:

REGULAR BRUTES have a selection of weapons to choose from:
Plasma Rifles x2
Spikers x2
Carbine x1
Bruteshot x1
Plasma Grenades
Deployable Cover (usefull in the tight hallways)
[The Regular Brutes get to teleport to either the rooftop, or topfloor]

Invisible Brutes have a limited selection of weapons, but enjoy Active-Camo:
Maulers x2
Beam Rifle x1
Firebomb grenades
Flashbomb
[The Invisible Brutes can only teleport to the topfloor]

Cheiftan gets only the Custom power-up & the hammer. (Poor Cheiftan...)
[The Cheiftan can only teleport to the rooftop]

I forgot to mention that the Brutes also have a Banshee on the rooftop, for bombing into the building through the windows.

Download Asset version link:http://www.bungie.net/Online/Halo3UserContentDetails.aspx?h3fileid=104268087
Download FFA Map link:Bungie.net : Halo 3 File Details

The Pics:

Overview of the Building.

Sample of the interior (This is on the 4th floor)

Peeking in through a window. (3rd floor)

The door leading to the stair-case to the rooftop

Showing the stairs that lead to the rooftop, the scoring zone and the banshee for the brutes to use

Overview of the rooftop

The "Regular Brute" Spawn room. Note the two teleporters that will lead to different floors.

The "Invisible Brute" Spawn. (This class only teleports to the top floor)

The "Cheiftan" spawn room. (The Cheiftan only teleports to the rooftop)