Monopoly
The original is The Landlord's Game, patented by Lizzie Magie in 1904. A Quaker sympathetic to Henry George's single-tax theory, she designed the board so players would feel, in their bones, how much land monopolies could hurt people. Before it was ever sold commercially, the board spread by word of mouth through Quaker communities — from Hoskins to Jesse, to Eugene, to the Todds, and on to Darrow. Along the way, street names and fixed prices from Atlantic City were added. In 1935, Darrow patented it and claimed he'd invented it in his basement. That same year, in November, George Parker of Parker Brothers himself visited Magie and bought her patent for five hundred dollars. Not out of respect — it's been pointed out that this was a corporate move to keep similar games from breaking Monopoly's own monopoly. The full story wasn't widely known until the 1970s, when a lawsuit over a game called Anti-Monopoly brought it out. A board built to teach against monopoly became the board of monopoly, and then the original creator's rights were bought up to protect that very monopoly — a triple reversal.
The myth, corrected
Monopoly was invented by Charles Darrow, unemployed, in his basement.
Darrow did take out a patent in 1935, but the original was The Landlord’s Game, patented by Lizzie Magie in 1904 (US patent 748,626) — a board built so that players would feel in their bodies how much the monopoly of land hurts people. It spread by word of mouth through Quaker communities, picking up street names and fixed prices along the way, and was then sold as a basement invention. That November, George Parker of Parker Brothers visited Magie himself and bought her patent for five hundred dollars; it has been argued that this was to keep a similar game from breaking the monopoly. The full story became widely known through a lawsuit in the 1970s.