Adaptation Overdosed: Not even taking the sheer number of Themed Stock Board Game versions or altered official versions into account, Monopoly has an utterly absurd amount of video game adaptations, nearly once a generation and sometimes more. It began with the Sega Master System version in 1988 and there have been new ones put out at a steady consistent flow since. One can possibly owe this to the fact that the game benefits tremendously from becoming electronic, as it cuts out having to handle all of the paper money that is constantly on the move during the game and greatly simplifies the auction process, and being the most recognizable board game in history doesn't hurt either.
The game's video game adaptations tend to include a lot of optional house rules that started out as unofficial house rules.
For an unusual case of the game acknowledging house rules, at least one printing mentions "no auctions", "Free Parking jackpot", "loans" and "deals not to charge each other rents" as popular ones, but tells you not to use them because they make the game drag on.
Easy Money by Milton Bradley. Officially, both games are based on an older game called The Landlord's Game, but Easy Money was released as a direct response to Monopoly's success. Continues to be published, under license, by a third party company.
Saidina is a Malaysian Foreign Remake of Monopoly going by a different name, with the settings changed (e.g. Atlantic City → Kuala Lumpur). In terms of gameplay, it's pretty much exactly the same (right up to using identical tokens!).
Another foreign remake is pre-Castro Cuba's Capitolio, which uses Cuban settings but otherwise has identical gameplay and even cards styled after those on Monopoly.
Incidental Multilingual Wordplay: Until 2009, when the original English title was restored, the game was commercialised in Italy under the name "Monòpoli", which sounds like an actual city name. This is thanks to the suffix "-poli" ("-polis") and the fact that the pronunciation moves the stress over the second O, while the word "monopolio" (monopoly, the economic concept) has the stress on the third O instead. There is in fact a real town called Monopoli in Southern Italy!
Technology Marches On: The main reason behind the creation of the "Electronic Banking" editions of the game, which replace the now-iconic paper Monopoly money with four debit cards and a card reader. Because who uses cash these days?
The 1989 pilot featured Patty Maloney playing the part of Uncle Pennybags and basically being a living token who moved per the dice rolls. The series replaced her with lights on the board.
Marc Summers and Peter Tomarken were both considered as hosts. However, when the show went into production, Marc was busy hosting Double Dare. Peter hosted the pilot, but his clash with the producers over Patty being treated as a thing rather than a person led to his being replaced.