But is Monopoly the best game metaphor? It's circular nature suggests a time loop, where you keep falling into the same traps (opponents' properties) over & over. If that analogy is apt, it would contradict TPTB's notion of time as a single timeline, continually snapping back into place despite the disruptions of free will. Plus, LOST hasn't had its characters play or talk about Monopoly, to my recollection.
The games that have appeared, in addition to this week's game of Risk:
http://www.lostpedia.com/wiki/GamesI would surmise that no game per se represents "the game" being played by Ben & Charles Widmore. Rather, the broad strokes of game playing - an agreed upon set of rules, a winner & a loser, a definitive finish line - are what's germane here. However, just as with kids who come across a grey area in a game where the rules are fuzzy, conflict is sure to erupt, and things get quite messy. Just like our latest tussle over whether Alex became fair game or not once Ben disavowed Alex as a legit, beloved daughter.