In this chapter, we define and give a brief history of exergaming and consider the evidence base, focusing particularly on multiple sclerosis (MS). Next we describe two case studies based on MS research studies we have conducted. The first, a laboratory-based clinical trial comparing active video gaming (AVG) to traditional balance training, illustrates the concept of ‘flow’, arguably a key characteristic of AVG. The second, a pilot study, demonstrates the use of behaviour change techniques in a physiotherapist-supported home-based AVG programme. Having earlier highlighted the 144importance of understanding users’ ‘lifeworlds’, we consider user perspectives of AVG (using MS as an example) as well as clinician perspectives. Finally, we reflect on why uptake of these technologies in clinical practice has been slow, suggest ways to improve the quality of exergaming research and reduce the evidence-practice gap and speculate on future developments in the field.