What if you had the chance to sit in on a course by a Nobel Prize winning economist? What if it was "free"? Well, “free” in the sense that there's not a monetary payment necessary. As we all know, there's an opportunity cost. This may take about 25 hours or so of your time. You probably won't get a lot that you can use directly with your students, but I suspect you'll gain a lot more understanding of an important topic that your students will benefit from.