Sure, "Shame," Steve McQueen's drama about a man battling his sex addiction problem in modern-day New York, was always going to be a tricky thing to get past the notoriously persnickety MPAA. But looking back on it, did the movie really deserve its NC-17? Especially given the amount of frank sexual content and (what's worse) violence that's on basic cable these days? The answer, most assuredly, is no. But if one moment secured the potentially lethal rating for the movie, it's the opening shots of the film, which feature star Michael Fassbender walking around his cramped Manhattan apartment completely in the buff. Most reported this like it was a sideshow attraction (you get to see him pee!) but it’s the offhand way that McQueen treats the nudity that makes it so powerful, something he does again when he introduces Carey Mulligan in a similarly starkers fashion. It's just parts, y'all.

Julie Christie in “Don’t Look Now”
“Don’t Look Now”
One of the reasons the "Don't Look Now" sex scene has endured for so many years, despite the film's place in relative obscurity (besides it being immaculately put together and often admired to the point of imitation), is that rumors have persisted that the scene wasn't, er, simulated, and that Julie Christie and Donald Sutherland were actually getting busy on set. It's easy to see where these rumors came from (even if they seem largely implausible) as there's a lot of full-length shots in here, which give it even more power. During most sex scenes, only specific body parts are highlighted (a right butt cheek, let's say, or a left breast, an arched back, whatever), which is hardly how it works in actual sex. But here director Nicolas Roeg showed off both of his actors completely, making this a sex scene that is also a bona-fide nude scene. Weird that this is the exception and not the rule.

Heather Graham in “Boogie Nights”
“Boogie Nights”
Nudity in movies can express a lot of things, and one of them is unpredictability. In Paul Thomas Anderson's "Boogie Nights," an Altman-esque epic set in the San Fernando Valley during porn's pre-VHS 1970s heyday, an early nude scene acts like an exclamation point, popping up at a moment when you're absolutely not expecting a flash of full-frontal female nudity (even if it is a movie about porn stars). The scene occurs when porn impresario Burt Reynolds brings home young busboy Mark Wahlberg and introduces him to one of his stars, played by Heather Graham, who quickly whips off her onesie, exposing her nubile frame and jolting an audience that, up until this point, had been exclusively dazzled by the brisk characterization and virtuoso camerawork. Graham, for her part, is effervescent and charming and goddamn flawless as the girl next door gone to the dark side.

Michelle Williams and Sarah Silverman in “Take This Waltz”
“Take This Waltz”
Sarah Polley's second film, "Take This Waltz," is equal parts brilliant and frustrating, a look at how the comfortableness of a steady relationship can curdle into something much uglier. And while there is one sequence that certainly has an amount of kicky sexuality (an amazing sexual montage set just as our main character enters a new relationship), the other nude scene is so plain that it almost feels like commentary on the nude scene itself. Even though everyone is naked, it's the anti-nude scene. It involves Michelle Williams, Sarah Silverman and Jennifer Podemski, all in a locker room shower, talking about bathing. They're all completely naked, but the scene has the matter-of-factness of an Aaron Sorkin walk-and-talk sequence: it's all about the dialogue, the three women just happen to be naked. And nobody looks like a movie star, with Polley's camera capturing the women in a wide master, looking natural and real.

Jason Segel in “Forgetting Sarah Marshall”
"Forgetting Sarah Marshall”
Nudity can provoke, titillate or disarm, but it can also be used as a punchline. This is exactly what writer/star Jason Segel and director Nicholas Stoller had in mind for the sequence where Segel, trying to inject a little daylight fun into his relationship with hottie television personality Kristen Bell, instead ends up being dumped, but still refuses to put on clothes. The sequence starts off goofy, but somewhat relatable, and ends up kind of melancholic and sad, yet still awkward and relatable -- in hindsight it's kind of miraculous. And Segel is a real trooper. It takes a lot for anyone to let their junk hang out onscreen -- it's another thing altogether to do that and actually encourage people to laugh at you/it.