From the introduction:
A PORTABLE RPG is designed to be played almost anywhere, quickly and easily. Take it to school, play in line at the theater, in the car, or at a convention. All you need is a couple 10-sided dice, a copy of the rules, and a few index cards with character, bad guy, and other statistics. To play somewhere that you can't "spread out" just bring a cup to roll the dice in - a small paper or Styrofoam one will do.