po·ta·to move·ment (noun): A practice emerging in Greece whereby municipalities coordinate direct sales of potatoes and other agricultural products from producers to consumers. Consumers benefit from deep discounts over retail prices, and producers benefit by being paid immediately for their goods.
An article in The Guardian described how the potato movement works in practice:
As devised by [agricultural marketing professor Christos] Kamenides and his students, it's a simple system. Their brainwave was to involve Greece's local municipalities, lending the movement a degree of both organisation and official encouragement that it might otherwise have lacked.
So: a town hall announces a sale. Locals sign up for what they want to buy. The town hall then tells Kamenides the quantity required and he and his students call local farmers to see who can supply it. They show up with the requisite amount of produce at the appointed place and time, meet their consumers, and the deal is done.