I admit, I wasn't too sure of Wreck-It Ralph, Disney's fall 2012 computer animated feature, at first. The combination of Disney's fairly weak reputation in terms of storytelling still lingering since the Eisner era, and the poor understanding of video games by Hollywood wasn't encouraging.
This wasn't an issue. First, the executive producer is John Lasseter of Pixar fame, and they managed to deftly created a universe where it is a blast for video game enthusiasts but enjoyable for the mainstream film audience.
The movie begins in a premise similar to TRON (which Disney also owns, so no fear of copyright infringement), wherein behind the screens of the arcade, video game characters "live" and do things for the player. In the game Fix-It Felix Jr., Ralph, a hulking giant, climbs out from the dump, and breaks windows of the condos, letting the player-character "Fix-It Felix Jr." to fix windows that Ralph breaks, while avoiding bricks, and eating pies for power-ups. After a disastrous 30th Anniversary celebration where Ralph isn't invited and with little help from his "Bad-Anon" group (a meeting of video game bad guys), Ralph decides to "go turbo" and game-jump, causing major trouble everywhere.
While the games visited, "Fix It Felix Jr.", FPS "Hero's Duty", and the sugar-coated racing game "Sugar Rush", are all fictional, the influences on them are noticeable ("Sugar Rush" is an over-the-top Mario Kart-type parody, complete with weapons to get ahead, for instance).
However, that's not to say there aren't a bunch of cameos. Zangief and Q*Bert have speaking roles, real arcade games are seen, Bowser (but no Mario), Pac-Man, Sonic (which has a few minor speaking roles, announcing PSAs in a manner similar to the "Sonic Sez" segments), with references abounding, from the obvious (the Konami Code) to the subtle (graffiti that reads "Aerith Lives"), and others that I've undoubtedly missed. You can also try to spot the similarities between the movie and the webcomic Kid Radd (which explores similar themes, right down to parody games and the true villain reveal), and Who Framed Roger Rabbit? (also in more ways than one).
Alas, there's a few things that I could've wished for it be in there...there are mentions of a fourth video game "Extreme Easy Livin' 2", which was a combination of The Sims and Grand Theft Auto, or a proper Mario cameo (and not just a mention). I'm also disappointed because although there's great fodder for a sequel (especially since Disney now has LucasArts to do stuff with), the plot got resolved.
EDIT: I'm sure that someone watched this Blur commercial, which features another ridiculous Mario Kart parody undoubtedly influential to the movie's universe.