Sufferers of cystic fibrosis and other chronic lung diseases benefit from daily physiotherapy such as Positive Expiratory Pressure (PEP). For children, however, such repetitive daily exercises become a burden and may lead to confrontation with the family. Using a system comprised of a PEP mask, a computer- connected pressure monitor and a suite of games of varying types, a series of tests will determine with both objective statistics and subjective feedback how effective the system is at encouraging children and young adults to participate in daily therapy. With longer and more advanced games, coupled with unobtrusive data gathering functionality, we determine what effect long-term use of such a game system has on young sufferers. The study has shown that games based PEP physiotherapy is a desirable, viable alternative that can perform at least similarly to the existing approaches in terms of the amount of time children spend engaging in breathing exercises and with potentially many additional benefits including the capture of detailed data about the amount and quality of physiotherapy which is currently impossible with conventional, non-computerized methods.