DotE and BotE are big fans of NPR’s Planet Money, and while I enjoy certain episodes, I am not a regular listener. DotE and BotE persuaded me, however, to check out Planet Money’s “Summer School series,” which is an ongoing group of episodes that act as a free Introduction to Economics class. “Summer School” illustrates basic concepts like the “sunk cost fallacy” by revisiting some of the podcast’s best stories and adding commentary by (married) economics professors Betsey Stevenson and Justin Wolfers. I strongly recommend the series to any adult who wants a fun refresher course and any pre-teen or adolescent-aged student looking for an amusing and clear way to learn basic economics. Their main point: Economics is not about money. It’s about decisions.