"Capture the Flags" is the side quest in Borderlands 2
Sidequest (Optional Mission)
How to start
Speak to Brick in Sanctuary.
TURN IN: Brick
Skin and XP
In their long-running war against Mortar's Sawtooth Clan, the Slabs have never captured any of Mortar's territory. Brick is hoping you will change that. If you can raise three Slab flags in Sawtooth Cauldron, that Slabs' awesomeness as a bandit clan will be solidified.
Raise Slab Flags over Sawtooth Cauldron.
Slabs fo' life.