Unlocked by inputting the Konami Code.
A Borderlands 2 Easter Egg called Extra Wubs mode has been discovered, as reported by MP1st.
To access Extra Wubs mode players only need to input the Konami code on the game's title screen. That's: Up, Up, Down, Down, Left, Right, Left, Right, B [crouch for PC/PS3 players], A [jump button for PC/PS3 players], Start.
You'll now find Extra Wubs mode in options menu under the gameplay tab. Sadly, Gearbox admits the mode does absolutely nothing.