In the episode "A Midsummer Nightmare", Zack and Cody are trying out for the school play. If you pause the TV when it shows the cast list, you will see under the list of charecters, they put PTHESEUS. I think they meant "Thesus", who is the father in the play.
Hey, that's pretty cool. I'm in drama club and we're putting on "A Midsummer Nights Dream" right now. Actually, I'm in costume for it and we open in a hour! I watched this episode when I read this, and I noticed it, too. Thanks!