1. A method of providing a graphical user interface on a computer system, said computer system comprising a CPU, a memory, and graphics display screen, said method comprising the steps of: providing a plurality of spaces, each of said spaces comprising a graphic background image; organizing said spaces in a directed graph structure, said spaces connected together with a plurality of portals; locating said plurality of portals in said spaces, each of said portals having an associated target space such that said portal connects the space said portal is in with said associated target space, each of said portals comprising a graphic icon; rendering a graphic background image of a first space and portals located in said first space on said graphics display screen, said first space having at least a first portal; receiving input from a user, said input comprising a portal selected from said portals located in said first space; and rendering a graphic background image of a target space associated with said selected portal on said graphics display screen; such that said user can move between spaces in said directed graph structure by selecting said portals within said spaces.