Jason Biggs, Everett

Sex can be serious, sex can be dramatic, but sex can also be pretty hilarious. In this week's "Don Jon," Joseph Gordon-Levitt adds a comedic spin -- along with some Jersey flair and muscles -- to the heavy topic of sex addiction.

Writer, director and star Gordon-Levitt plays the title character, your typical gym rat womanizer who can't (and doesn't want to) stay in a committed relationship. But when he meets the beautiful and charming Barbara (Scarlett Johansson), he attempts to recover from his sex and porn addiction and begin his first real relationship. Real love over porn sounds like a no brainer, but for this guy it's a bit of a struggle.

From virgins desperate to lose their V-card to a teen's porn star fantasy come true, we've seen every kind of kinky act in the movies. But Hollywood doesn't always get the sexy stuff right. Sometimes there's disappearing cleavage or self-refilling beer cups. Below, we've rounded up 10 movie mistakes from your favorite sex comedies.

As always, photos are courtesy of MovieMistakes.com.

Don Jon- Trailer No.1