One I use for random gaming needs, but requires two brains, if I want to emulate a dN die (d6, d10, d20, whatever) is I think of a number between 1 and N, and the other person does the same. Then add them together and mod by N. Works well enough, although you can get into game theory and the results aren't very random because we tend to pick certain numbers.<p>Thinking about it, I wonder if both people picking multiple numbers and adding them all up mod N would improve things.