Obelisk
So I just got the mythic map pack and figured hey, I'm going to make a map. This is the result. I don't know a ton about pro forge methods and concepts but I think it is at least a decent map.
This map is centered in the Crypt area of Sandbox. Design is for FFA matches from 4-8 people, featuring a lot of close quarters combat area along with some long sight lines and open areas for ranged attack. It began as a fun remake of the Goldeneye 007 map "Temple", but beyond one section of the room the resemblance ends.

Partial Overview
Weapons
1 Shotgun
6-7 Battle Rifle
2 Needler
4 SMG
2 Spiker
2 Plasma Rifle
2 Mauler
2 Carbine
1 Rocket Launcher
1 Spartan Laser
2 Magnum
2 Plasma Pistol
2 Brute Shot
6 Frag grenades
6 Spike Grenades
Equipment that is limited to 2 Bubble Shields, 1 regenerator and 1 power drain. Also includes an oversheild and active camo.

Other Side Overview

Corner I Missed

A Dark Hallway

Under Center Platform
Better Overview, Center Platform
Basically most of the game surface is on the ground floor, the exception being the 'center' platform with the rocket launcher on it and the two ramp areas that lead up to it. The center platform has a room underneath with various weapons and three access points. Some preliminary testing with friends got some of the major issues. Being new to forging maps I'm not sure what exactly to do to improve it, any specifics on weapon layout, spawn points, map changes I would be glad to hear.
Download:
Halo 3 File Details