Here is an arcade cabinet tiny enough to fit in your bag that lets you play fun, classic games anywhere. The Cupcade Raspberry Pi Arcade Cabinet comes with almost everything you need to build it and learn electronics in the process. You get a PiTFT 2.8″ display, mini thumbstick, mini arcade push buttons, and other components.
Simply bring your Pi model B, and you are ready to go. Horizontal and vertical modes are supported.