One Piece: Pirates Carnival [PSX]

Unlock Skypiea 1
After getting the Grand Line 3 board, make sure that the PS2's time and date match the actual date and time. Go to Board Game then go to Password. Entered going left to right, and once you reach the 3rd column, go to the 2nd row. Enter the password Triangle, Circle, Circle, Square, X, Circle, X, Triangle, Triangle.

Unlock voice collection
Simply play each of the games in Member's Game and the Captain's Game once and each of them will unlock the voice collection (you don't have to win the game, each game will only unlock one voice collection)

Unlocking more games, new board, and cards
Play the board game, and in the end, all the games that you've played will be unlocked in the versus mode. This will also unlock new bigger boards, and all the cards that appear in the board game will also be unlocked in the gallery.