Instructions
Play through "New Super Mario Brothers Wii" until you reach level 6-5.
Play through level 6-5 until you reach the flag at the end of the level. Do not use the secret exit that transports you directly to the castle.
Press left on your directional pad to walk Mario to the left on the World Map. Mario will automatically hop across the chasm using the pipes that protrude from the mountain side.
Press "2" when you reach level 6-6 to begin playing.