I live near a smallish town that hosts an international business meeting twice a year. It quadruples the size of the town, and there are nowhere near enough hotel rooms. Hundreds of people within a 30 minute drive rent out their houses for the week (modest, fancy, whatever). They camp, move in with family, or take vacation. There are real estate rental companies that do nothing but manage these transactions. My boss rents out her 8,000 square foot monstrosity to the same 8 people twice a year and makes about $30k per year.