Scrolling pixel art FTW!
This was made from a video I saw for a server shortly after pistons showed their awesome...err...rods? To minecraft. The video didn't show how it worked, but it was common sense to build one based off the idea.
So here's mine! A scrolling Boo from Mario.

Also, please note, that there will be a video of this thing in action shortly. My laptop lacks the RAM to record...

Additional Notes

If you want to build your own, here are some things to keep in mind:

• This will lag servers, so make some form of an on/off for the clock used.
  
  
• Pistons can only push 12 blocks, meaning you can only have a total canvas size of 22 wide. Yes, 22, you need those two spaces for the pistons to work properly.
  
  
• ALWAYS test the pistons before building the art in it! Just place some random blocks in the machine to test the cycling and the clock system you use.
  
• You can, if you want, use a flip-flop button, and wire that into the clock as a simple on/off button verus the button and lever as I have. However! I personally would say to keep a lever in the system, as it is a solid visual that the machine has been turned off in the event of lag (if this is built on a server)