The new "Heroic Map Pack" is available for 'Halo 3.'

From Major Nelson:

The Heroic map pack contains three new maps, each presenting a totally different play style. Standoff’s symmetrical valley, with its entrenched bases and fields of boulders is ideal for mid-sized objective and Slayer game types, while Rat’s Nest’s vast, labyrinthine passages bring something quite new to the Halo multiplayer experience – an indoor vehicle paradise, strongly influenced by the Campaign mode ideal for big team battles. Finally, Foundry is the ultimate Forge map – players can edit every single object in this voluminous industrial warehouse, place stairways, walls, bridges and tunnels to create an entirely new play space and build almost any kind of map they can think of.

AND for all you 'Rock Band' members, check out the new "Punk Pack" with these songs:

• "I Fought the Law" by the The Clash
• "Rockaway Beach" by the Ramones
• A cover of "Ever Fallen in Love" by Buzzcocks
(Available for PS3 and 360)