I went to the Club Penguin mod site which is icebox.clubpenguin.com — you will not be able to enter the site because they blocked it, i had a sneak peak on the current projects for 2006 and discovered that ninjas will be implemented later on November.
How to be a ninja
First, go to the dojo which is located at the upper right part of the mountains then stay on one place, don’t move or even walk for 30 minutes. The max time limit for idles is 10 minutes, to extend the time simply talk, dance or throw snowballs. After that, you will be able to see three penguins with blue and black bands then they will ask you if you want to be a ninja, do this quickly or you will miss the chance to be one.
Note: Don’t do it today because it will never work, just try it on November. Im not sure if they will be implementing next month, so don’t blame me if they dont.