In one episode of the Make: television show I do an Input >> Arduino >> Output demonstration to explain how the microcontroller reads a button press and plays a light pattern on some LEDs. To keep things clear visually, I mounted the buttons in one MAKE Project Tin, the Arduino in the middle, and the LEDs in another tin. I also used one of these tiny breadboards to wire it up (I ran out of time to solder anything). All hail the humble Altoid tin!