Hollywood loves to point out how zany it is when a man wears women's clothing, and have even been able to find writers who love the idea enough to write a two hour long movie about it. Here they are in chronological order.
Some Like It Hot (1959)
A movie about cross-dressing came out in the 50s?! It did. And surprisingly, no one got pissed. Oh wait, The Catholic Legion of Decency were shockingly PO'd by the movie, and put it on a list of movies considered indecent.
Anyway, the plot to Some Like It Hot centers around Joe and Jerry played by Tony Curtis and Jack Lemmon, respectively, who witness a mob murder. When the mobsters realize there are two witnesses, they do what mobster hitmen do, and gleefully decide to murder these two guys.
That's when Joe and Jerry realize "Hey, they're looking for guys!" and throw on some ladies clothing, complete with thong, as suggested by their friend Sisqo, played by Sisqo, maybe. They join an all girl band headed for Florida where they meet "Sugar" Kane, played by perenially-masturbated-to Marilyn Monroe. They fall in love with her and vie for her attention, all while pretending to be women. A rich dude even falls in love with Jerry. The American Film Institute labeled the movie as the greatest comedy of all time.
Dustin Hoffman plays Michael Dorsey, an acclaimed but high-maintenance actor who has difficulty find work due to complaints of his perfectionist attitude and demands for greatness from his fellow actors. When he auditions for a part in a soap opera called "Southwest General Hospital." He fails to get the part, but decides he needs to cross-dress and audition as actress "Dorothy Michaels" to get a female part on the same show. Miraculously, he gets the part, and becomes one of the shows most popular characters.
Of course, he falls in love with and wants to bang his co-star, played by Jessica Lange. He makes passes at her both as Dorothy and as himself, to no avail. Finally, during a live taping of the show, Michael comes clean, but under the guise that he was playing a character meant to cross-dress as the characters sister, and was out for revenge. Now out of obligations to play Tootsie and no longer needing to be Dorothy Michaels, he is free to pursue Julie, although she's pretty pissed.
Mrs. Doubtfire (1993)
Robin Williams plays Daniel Hillard, a voice-actor in San Francisco who, much like the real Robin Williams, isn't able to be serious, and annoys a lot of people. After a work incident in which he refuses to play a character he feels is advertising cigarettes to children, he is fired. Then he throws a rockin' party for his son Chris's (Matthew Lawrence) birthday although his mother Miranda (Sally Fields) had forbade him to have one, due to his shitty grades and overall stupidity. Enough is enough, and Miranda divorces Daniel.
Since he's unemployed, the judge declares that Miranda get main custody of the children, which gets Daniel upset. Deciding he can't hang out with his kids on weekends only, he devises a scheme where, with the help of his make-up artist brother, he will appear to be the nanny that Miranda wants in order to take some of the workload of child-care off of herself. He gets the job as Mrs. Doubtfire, a British woman with a history of childcare. After a series of hilarious mishaps, Daniel finds himself in a situation requiring him to be both Mrs. Doubtfire and himself at the same time, at a restaurant, where his ruse falls apart.
To Wong Foo: Thanks For Everything, Julie Newmar (1995)
You're correct, this movie DOES have a ridiculously long title, and the plot centers around three drag queens; Vida Bohemme played by Patrick Swayze, Noxeema Jackson played by Wesley Snipes, and Chi-Chi Rodriguez played by John Lequizamo. The three decide to drive across the country to take part in a gigantic drag-queen convention, but on the way, they're pulled over by homophobic police officer Sheriff Dollard, who attempts to sexually assault Vida, and much to his chagrin, finds out she's a dude...with a penis. He/She knocks the sheriff out, and the three think he's dead for some reason.
At a nearby rest stop, their car breaks down, forcing them to spend time in the small town until it can be repaired. After Sheriff Dollard recovers, he decides it's time for some serious gay-bashing, and begins a hunt for the three men. When he finally has them cornered, the townspeople, once bigoted and small-minded, stand up to him and protect them. Upon making it to LA, Chi-Chi wins the title of drag queen of the year, and Julie Newmar herself even puts the crown on his/her head. Robin Williams makes an appearance in this film as well.
The Birdcage (1996)
When Armand Goldman played by Robin Williams, who is apparently an enormous advocate for cross-dressing, finds out that his son Val (Dan Futterman) is getting married and is bringing his fiance Barbara Keeley (Calista Flockhart) with him to visit, he knows it will be a problem. That would be due to the fact that Barbara's dad (Gene Hackman) is a United States Senator in the ever-accepting Republican party, and Armand is ridiculously gay and Jewish. He and his partner Albert (Nathan Lane) even own a gay nightclub in Miami. Since Barbara knows all of this and realizes the implications it could have on their marriage, she asks Val to somehow fix the situation so that her parents think his family is the traditional type. They decide to get Val's biological mother Katherine in on the act, and she agrees.
When Armand asks Albert to stay away because he's super flamboyant, he locks himself in the bedroom. As dinner gets started, Katherine is stuck in traffic, and Albert emerges dressed as a woman and pretends to be Val's mother. When Katherine finally arrives and introduces herself as Mrs. Goldman, Barbara's parents are confused. The home has been surrounded by paparazzi as a result of a scandal related to one of Senator Keeley's friends, and being seen in a gay nightclub will only make matters worse. The group escapes the home dressed in drag, fooling the paparazzi.