Many believe humanity's future lies among the stars, colonizing distant planets around alien suns, or perhaps building artificial worlds, space habitats, and megastructures. But what if instead of traveling to worlds far away in outer space we create virtual worlds to live in instead, colonizing inner space? We will explore this possibility of simulated universes and what it might mean for humanity, and also ask if this might be a solution to the Fermi Paradox, the strange absence of other life in our own universe.