Online service Zazzle basically prints on anything. Want a one-off t-shirt or mug? They got it. It's somewhat like Ponoko or Shapeways, you either generate your own design or choose from one of theirs, and then add-to-cart and the item is manufactured and gets mailed to you. Which is not necessarily all that interesting -- countless services will provide that service.
Sounds cool! I could think of plenty of T-shirt slogans. We could have PC Pals mugs printed!