Kudos to dealbot who alerted me to this one, and who must still be stuck camping in the rain. :)
Gearbox have really been pumping out the Golden Keys lately. These are for the Pre-Sequel version of the game. They're 'universal' so should work on any platform, but you don't need to own the game to redeem them. These are not codes to unlock the game, they're only for receiving special loot in-game. They can be redeemed in-game or through your SHiFT Account online (membership is free).
There are two codes worth 5 keys each:
WK5JB-6RKKR-FHBFB-T3B3B-ZJ9J3 - expires 21 Sept @ 11:59pm US Eastern time
WCKBT-SRC5F-FH36J-3B33J-SFWXB - expires 21 Sept @ 11:59pm US Eastern time