Technologies such as Simulation and Virtual Reality will dominate the entertainment and science forefronts well into the next Century. Since early childhood, we have always learned by role playing and building models of things. With today's computer prices, personal computers are highly affordable. Armed with your computer, you can proceed to build models of reality and ``let them loose" to see what happens and to learn more about reality by modeling it. While what we may do today may be primitive by standards set in science fiction shows such as Star Trek (The Holodeck) and Lawnmower Man, the present computer simulation discipline will lead the way to these eventual goals. The key word is ``digital" as pointed out by many such as Nicholas Negroponte at the MIT Media Lab in his recent text ``Being Digital." We want to create digital replicas of everything you see as you look around you while reading this article. When you want to construct a digital world, you will pick digital objects, using a 3D, immersive construction tool to put them together. The digital objects may be located anywhere on the Internet and you will use help tools (or autonomous agents) to locate the building block objects for your digital world. Some of this type of work is being done in Distributed Interactive Simulation which is a thrust pioneered by the Department of Defense. The implications of these types of simulations are profound since the idea of distributed simulation has enormous potential, also, in industrial and entertainment fields.