The problems of producing a software system to assist in the rehabilitation of people who have suffered serious traumatic brain injuries are described. In addition to this primary use, therapists need the system to evaluate, monitor, and for measurement purposes. The challenges of ensuring a high level of usability by incorporating the best of graphic and HCI design into a well established software engineering methodology are discussed, as well as the details of the specific approach we designed. The software needs to be repeatedly used and enjoyed both by the patients and by the therapists. The challenges to writing software to be used by such disparate groups are significant, and there is currently very little software that has been written specifically for this user group. As we discovered, many of the standard software design paradigms are inappropriate for users suffering from brain traumatic injuries. The resulting suite of programs is now in use at a rehabilitation hospital in Victoria, and we report on their successful adoption.