Gearbox posted the following shift codes on their blog, giving players a few gifts for St. Patty's day.
To receive your celebratory Zaford gear, including special green skins for each character and a Chulainn SMG that will be the the same level as (and appear in the backpack of) the first character you load, enter the SHiFT codes below into Borderlands 2:
PC / Mac Zaford Gear SHiFT Code: KTCBJ-C9RTC-BSFTJ-33TT3-FBWHF
Xbox 360 Zaford Gear SHiFT Code: KJCJ3-RCWC6-5K9BF-WFBT3-3WFKK
PlayStation 3 Zaford Gear SHiFT Code: CTK3B-99K3J-XXKW3-ZTWTJ-HJH5J
360, PS3, PC