The "Borderlands 2: Add-On Content Pack" bundles together all the previously released digital content up to the second add-on campaign on to a single disk for $29.99 starting on Feb. 26. The content included would normally cost $40 downloaded through PSN or Xbox LIVE.
"Captain Scarlett and Her Pirate's Booty", "Mr. Torgue's Campaign of Carnage" and Gaige the Mechromancer are the main draws of the "Borderlands 2: Add-On Content Pack" but there are some additional goodies as well. There's also the Creature Slaughter Dome battle arena where players can earn Mad Moxxi's rare rocket launcher, the Gearbox Gun Pack and Skyrocket Grenade, additional heads and skins, and a a Golden Key to unlock rare loot from the golden chest in Sanctuary.
Presumably, a second add-on content pack will be released in the future following the release of the fourth "Borderlands 2" DLC and will include "Sir Hammerlock's Big Game Hunt" plus other recently released DLC.