MOOCs--massive open online courses--are all the rage these days, with hundreds of thousands of participants signing up and investors plunking down millions to get a piece of the pie. Why is there so much excitement about this new disruptive form of online learning, and how does this model apply to professional learning for teachers? Traditional educational institutions will need to consider what, if any, part they want to play in the MOOC space and how they can best serve their on-campus learners, as well as the broader universe of potential students. For lifelong learners, MOOCs offer unprecedented opportunities. Every educator should participate in or lead a MOOC to appreciate this new form of learning and to bring its strongest benefits to their own classrooms. Everyone benefits where there are so many new learning opportunities available.