Suddenly Sober

A couple of characters are engaging in a night of heavy drinking, possibly at a bar or Wild Teen Party. After a series of wildly hilarious shenanigans that would only be engaged in by the very intoxicated, possibly summed up as a Binge Montage, the characters need to have a Very Serious Conversation. Luckily, they become Suddenly Sober, and can speak all the plot-relevant dialogue that will advance the story exactly as required, without once spotting a pink elephant or declaring "I love you man... no, no, but, you... I love YOU man."

Suddenly Sober is the moment in a movie or TV show in which a drunken character suddenly transforms from a word-slurring, sidewalk-tripping, projectile-vomiting mess to a highly-coordinated, quick-thinking, somehow enlightened (and much more sober) version. This could be brought about by some sort of crazy action sequence, a sudden realization, or any other sort of device that moves the plot along. Usually results in uncannily clear thinking or cat-like reflexes, depending on the situation. This trope can also apply to characters who are high, tweaked, etc. and suddenly sober up.

Anime and Manga

 * First episode of Black Lagoon. Revy and Rock have an impromptu drinking-competition in a Bad Guy Bar, and both of them are looking extremely sloshed - then a bunch of mercenaries shoot up the place with heavy machine guns and grenades, and they all have to crawl to safety and drive to safety - which they accomplish without so much as a hiccup. Perhaps justified for Revy, since she's a top-grade Action Girl and all-round Badass, but Rock is just a Japanese salaryman who gained his alcohol-tolerance from getting dragged out drinking with his superiors all the time. Being able to snap back to sober that quickly seems like it should be beyond him...
 * Justified in Ghost in the Shell, since the protagonists are cyborgs who can have the toxins filtered out of their blood immediately. In the first movie, The Major willingly allows herself to get drunk by disabling this function.
 * During the Axis Powers Hetalia Christmas 2007 strips, a cheerfully drunk England is told by Finland that one fan wants his advice on what to do about a broken heart, whereupon he suddenly becomes sober and sad as he reveals that he himself has suffered from a broken heart for at least 100 years and knows all too well what heartbreak feels like. Hanatamago even lampshades this: "He suddenly snapped out of it!"

Comic Books

 * The Sandman: Clurican the Faerie did this at the end of the World's End arc--he was completely soused for most of the episodes, then suddenly sobers up (as the storm blows itself out).

Fanfic

 * Played with in the Naruto fanfic Everto. When Sasuke is injured badly, Naruto calls up a drunk Tsunade and uses his demon Compelling Voice to make her sober enough to treat him. Apparently he did it mostly unconsciously.

Film

 * 10 Things I Hate About You: Kat shows up at Bogey Lowenstein's party, gets trashed on tequila and entertains revelers by dancing on a table. She collapses into Patrick's arms, and almost passes out when he turns his back on her. After stumbling up a hillside, falling off a swing and throwing up on Patrick's shoes, she spends the ride home engaging in witty repartee and insightful analysis of her social life.
 * Mean Girls: Cady throws a party, her friend comes by and calls her plastic, she suddenly sobers up and tries to get people out of the house.
 * Raiders of the Lost Ark: Marion Ravenwood drinks the large man under the table during a drinking competition at her bar, and is subsequently confronted by Nazis looking for an amulet her father owned. Even though her drunkenness was an act to turn the betting odds, she shows no sign that she'd just downed what had to be more than a dozen shots of hard liquor.
 * Adam from Hot Tub Time Machine takes coke, weed and mushrooms in his hotel room and can't even get up from the floor. Then his son bursts into the room and tells him he needs his help. Adam is completely sober in the next scene.
 * Iron Man 2: Tony is completely wasted during the party at his house, but when Rhodes shows up to fight him, Tony is still able to fight effectively.
 * Independence Day: David (Jeff Goldblum) has his inspiration for how to use a virus to hack the alien invaders' computers while too drunk to stand up. He then manages what appears to be a highly complex programming task without missing a beat.
 * In the Sinbad comedy Houseguest, the main character, posing as a reknowned wine expert, manages to bluff his way through a wine-tasting party by getting everybody else roaring drunk. A group of upper-crust white folk do not remove their pants and get down to "Brick House" when mildly tipsy. However, a scene later that very night has the hosts perfectly sober, and nary a hangover the next morning. And how did they drive everybody home that night? However, the movie is such a mess in the editing department that this seems to be just another oversight.

Literature

 * Good Omens: Aziraphale and Crowely, an angel and a demon, get extremely drunk once they figure out that the apocalypse is coming. Then, when they decide they need to talk seriously about it, they force themselves sober. It's apparently an unpleasant experience.
 * Justified in a Discworld book. There are some things alcohol can't cut through, and right in front of you is one of them. Another is Klatchian Coffee.
 * The sudden, horrible realization that you're in the Shades after dark will also "do the icy work of a good night's sleep and several cups of coffee".
 * In The Cat Who Ate Danish Modern, photographer Odd Bunsen negotiated a balcony several stories up to retrieve a cat...while completely drunk. He soon sobered up when he found the dead body of interior decorator David Lyke.
 * In In Enemy Hands, Admiral Tourville is driven to drink once he realizes that the Honor, who he considers a Worthy Opponent, is going to be abused and murdered on trumped up charges for propaganda purposes. When the half-mad propaganda minister who ordered it comes knocking on his door, he uses a device to sober up, with unpleasant side effects.

Live Action TV

 * Flashpoint: A radio DJ has a nasty bourbon habit and takes a guest hostage. As soon as he realizes the truth about what happened to his son, he stops leaning over the table like he's about to fall over and begins speaking in crystal-clear English.

Theatre
"Hilarion, who has been with difficulty restrained by Florian during this song, breaks from him and strikes Cyril furiously on the breast. Hilarion. Dog! There is something more to sing about! Cyril. (sobered) Hilarion, are you mad?"
 * Cyril in Gilbert and Sullivan's Princess Ida:

Web Comics

 * In Eerie Cuties a vampire bite, while not quite instantly, have this effect on the victim.
 * In Wapsi Square, Tepoz, the Aztec god of alcohol, is called in because bad things were going to happen if Jin didn't sober up quickly.