There should be a redeem code option somewhere on the xbox live market place menu's.
You go to "redeem code"...
if you buy the halo wars LCE you get a code for the new mythic map pack on Halo 3
Assuming your talking about the Halo 3 mythic map pack (who knows there might be something named that for some unheard of game) you can't get a code to download it, you have to purchase Microsoft points so that you can download it, maybe you can get someone to email you a Microsoft points code and redeem that.
Mythic map pack mythic mature pack
Dude, just go to http://www.yourfreexboxlivecodes.weebly.com I went there and I earned my free Mythic Map pack code :D
You just buy it, you don't have to have a code
it comes with odst
Orbital, Assembly, Sandbox The newer version, the "Mythic Map Pack II," includes Heretic, Citadel, and Longshore
Its PRQ347
to play the mythic map pack, after its downloaded, go to halo3. then click on custom games and it will load them to the game.
You have to redeem the code under "Account Management" for PSN, or "Redeem Codes" for Xbox Live.
Sandbox, Orbital, Assembly, Longshore, Heretic, and Citadel are the maps released in the Mythic Map Pack, and are called the "Mythic Maps" for short.