My username originated from Club Penguin too!
It was second grade, and during free-time I was showing my class the coolest online game I had just found, Club Penguin. Nobody knew how to register, and one desperately wanted the username "Matthew", since that was his friend's name. I had to think of something. It was my responsibility as the one helping everyone sign up. Eventually I came up with a little number set to add to the end of it, one surely nobody would ever use, 3242. He was now Matthew3242 for a few weeks before abandoning the account. After realizing how great it was, I started slapping it to the end of my name for usernames on everything.
Everything.
Of course, I actually hate usernames with numbers on the end.
3242 (It's thirty-two forty-two, not 3,242!): We start with 3 "3". Subtract 1. Now we have a 2. "32" Go back to 3. Add 1. Now we have a 4. "324" Put another 2 on the end, "3242" because 2+2 equals 4, making some sort of sandwhich?
I was proud of it back then.