This work explores the applicability of Massively Open Online Courses (MOOCs) for scaling High Performance Computing (HPC) training and education. Most HPC centers recognize the need to provide their users with HPC training; however, the current educational structure and accessibility prevents many scientists and engineers who need HPC knowledge and skills from becoming HPC practitioners. To provide more accessible and scalable learning paths toward HPC expertise, the authors explore MOOCs and their related technologies and teaching approaches. In this paper the authors outline how MOOC courses differ from face-to-face training, video-capturing of live events, webinars, and other established teaching methods with respect to pedagogical design, development issues and deployment concerns. The work proceeds to explore two MOOC case studies, including the design decisions, pedagogy and delivery. The MOOC development methods discussed are universal and easily replicated by educators and trainers in any field; however, HPC has specific technical needs and concerns not encountered in other online courses. Strategies for addressing these HPC concerns are discussed throughout the work.