Home telehealth applications are increasingly gaining in popularity among patients due their promise to use healthcare resources more effectively and hence to lower costs. Commercial telehealth systems usually employ patient stations and vital sign monitoring equipment in order to fulfill the need of medical professionals by enabling close monitoring of patients with severe chronic diseases. However, due their high cost, vendor lock-in, and doctor centric design, these systems are not suitable for general healthcare applications such as improving cardiac fitness, monitoring overall health, improving muscle strength and balance of elderly, or assisting with dieting programs. We argue that many of these goals can be supported in a cost effective manner by leveraging mainstream sensing devices such as game controllers and smartphones. Open-ended web-based telehealth systems can be integrated with such devices, in order to add a social component, collect health data unobtrusively, and provide feedback and health related information. In this paper, we systematically categorise and analyse consumer-level sensing devices in terms of their potential to extend the capability of telehealth systems. We show that the devices have immense potential as tools for therapy and rehabilitation activities, diagnosis, health monitoring and social support, and we reveal opportunities for professionals in computer vision, graphics and signal processing to participate in this trend.