Ready 2 Rumble Boxing: Round 2

At the character select screen press Left, Right, Up, Down, R1, R2. You will hear a bell if entered correctly.

Successfully complete arcade mode to unlock Freak E. Deke.

Start up your system without the disc inside, then access the ''System Configuration'' option. Choose clock adjustment and set the date to 12/25/2000. After adjusting the date, insert the game and begin. Choose arcade mode and highlight ''Selene Strike'' on the boxer selection screen. The words, ''Holiday Outfit'' will appear underneath her name.

Set the system date to December 25 to unlock an elf costume for Selene Strike and a snowman costume for Rumble Man.

To have the referee look like a leprechaun, set the PS2s internal clock to the 17th March.

At the Character select screen press:

LEFT, LEFT, RIGHT, R2, LEFT, RIGHT, RIGHT, R1, R1, R2

All characters will be unlocked. The question mark in the lower-right corner is the "Random fighter" button. Before you press X to confirm the fighter you want you can press the SQUARE button to change their costumes. You will have access to every costume, including the Holiday outfits. Not every boxer has a Holiday Outfit.

Note: This code also works in Championship mode.

To unlock GC Thunder's Uncle Sam costume, set the internal clock inside your PS2 to the 4th July.