Buy it using Microsoft points
Im pretty sure but not 100%, but its when the map has the same thing on eachside, like standard sandbox
For Halo 2 on PC there in lots of custom maps such as Vertigo 3, New Mombasa, and Halo sandbox beta 3.
Either buy the mythic map pack (worth 800 ms points) or get the multiplayer disc that comes with Halo 3: ODST.
The maps are Assembly, Orbital, Sandbox, Citadel, Longshore and Heretic.
Sandbox, Orbital, Assembly, Longshore, Heretic, and Citadel are the maps released in the Mythic Map Pack, and are called the "Mythic Maps" for short.
That is dabatable, however most people would say the DLC map Sandbox, especially if you manage to stop the guardians from killing players.
Go to the map Sandbox. Check if you are using forge. Use 2 double walls and 2 blocks.
in sandbox mode
It will have a different campaign mode and all of the halo 3 maps but it will also come with both halfs of the Mythic Map Pack (Assembly, Orbital, Sandbox, Citadel, Heretic, Longshore).
Forge.
assembly orbital and sandbox are apart of the mythic map pack so on April ninth download and find them*Spoiler Alert*Assembly-Orbital-Sandbox Skulls-http://www.youtube.com/watch?v=tYZhcJUzh98as for longshore, citadel, and heretic, you will have to wait for Halo: ODST. Sorry.
The Halo 3 Mythic Map Pack is scheduled for release on April 9th 2009. It will cost 800 Microsoft points and will include the three following maps: Assembly, Orbital, and Sandbox. You do NOT need the Halo Wars LCE to obtain these maps once they are released to the general Halo community on April 9th.