It goes without saying that you can do all kinds of fun things with a Raspberry Pi. The good folks at adafruit have put together a tutorial showing you how to make a portable Raspberry Pi with a 3D printed case. They used a Raspberry Pi model A+, PiTFT 3.5” display, Powerboost 500C and a 2500mAh lithium polymer battery to get the job done.
The above video provides you with more information about the Touch Pi. You can find the instructions here.