It lacks the official licence, of course, but Omerta: City of Gangsters is a game based on (or cashing in on) HBO's awesome series in all but name.
Currently in development at Tropico devs Haemimont Games, Omerta outlines the game as "starting with small jobs, his character recruits a gang and expands his empire by taking territory from other gangsters. Eventually he establishes his own crime syndicate and becomes the de facto ruler of Atlantic City."
Those with a longer memory than a recent TV series may also think it sounds like PC classic Gangsters: organised Crime. And it does! Which only makes this all the more promising.
Like Tropico, it'll not only be coming to the PC, but to the Xbox 360 as well.