Monopoly is a board game.
When Herb Powell visited the Simpson family, they played Monopoly. When Herb came to Ventnor Avenue, which Lisa owned, he became a bankrupt. Homer started laughing at him because the same thing happened to Herb got bankrupt in a real-life too and Herb punched him.
When an acid rain fell over Springfield, Marge suggested to play original Monopoly (mostly because they already had many versions of the game already, and Marge felt the original was weird enough as it is due to an iron piece being a land lord). They started playing, but when Lisa wanted to build a house on her property, she saw all houses are gone, because Maggie had stuffed them in her cheeks. Homer ended up on Bart's property, full of houses and hotels. Lisa then noticed that Bart was cheating, as he had made hotels from Lego. Marge said that it was just an accident, but Lisa thought that Marge defended Bart just because he had bought her a house on St. James Place. Homer and Bart soon started fighting when Bart insinuated that Homer won't be able to take care of Marge in response to Lisa's accusation. Marge and Lisa joined the fight to split them up. Scared, Maggie called the police. As the police arrived, the hat piece smashed through the window. Lou said that it was another case of Monopoly-related violence. Chief Wiggum then wondered how the Parker Brothers slept at night.