Water Wakeup

A character gets a Tap on the Head, or receives something else that knocks them out.

The next thing they (or we) know is that they're in a cell, either tied to a chair or lying on bed. Either way, they're rudely awoken by a bucket of cold water in the face.

This generally means the imminent interrogation will not be nice.

Alternatively, this can be done for laughs when a character who was simply asleep is woken up this way. In this case, the character doing the waking isn't necessarily hostile, but just not too worried about the sleeping character's comfort.

Almost always overlaps with Waking Up Elsewhere.

Examples of Water Wakeup include:

Anime & Manga

Samurai Champloo: In the first episode, Mugen passes out while fighting Jin in a burning building. He wakes up to a bucket of water, and learns he's going to be tortured and executed for killing the Governor's son.
This has been done at least once in Ranma ½ when Akane found Shampoo sleeping with an oblivious Ranma (she'd crawled into his futon sometime during the night), Akane woke him up with a bucket of cold water which, thanks to his curse, also turned him into a girl. Added hilarity came from the fact that Shampoo didn't know about the curse and was trying to kill "Girl-Type Ranma".

Films -- Live-Action

Pirates of the Caribbean
- The comedic version shows up in the first movie, as Captain Jack Sparrow and Will wake Gibbs this way. Then Will dumps a second bucket of water on Gibbs, and says "That was for the smell." To clarify, Gibbs was sleeping in a pigpen. After hearing Will's reason, he just looks surprised and nods.
- Again in the sequel, when Jack finds Gibbs asleep on the end of the pier-a pier notably short a ship. Gibbs is also found clutching a stuffed animal, and takes a second to comprehend the followup question regarding the absence of the Pearl.
In Blazing Saddles, Bart and Jim do this to wake up the now-securely bound-with-chains Mongo. Mongo casually breaks loose while yawning. (Fortunately, Mongo's in a good mood, considering.)
In The Princess Bride, Fezzick revives Inigo from a drunken stupor by shoving his head into buckets of cold and hot water.
In Talladega Nights the Ballad of Ricky Bobby, Ricky Bobby's father throws a bucket on him to wake him up... then throws another on him because he filled up two.
In Camp Rock, Shane Grey gets the comedic version from his uncle after refusing to wake up twice.

Literature

And again in the book version of Neverwhere. Hunter, Door's bodyguard, wakes Richard up with a bucket of water, and then wakes Door much more gently, after both have passed out drunk.
Happens to Nathaniel in book 2 of The Bartimaeus Trilogy. Bartimaeus got bored.
In Stephen King's The Stand, Randall Flagg uses this method to get the attention of a contact who has needed information, but is dying of the super-flu.
In Iain Banks' Whit, after offers of coffee and threats of excommunication fail, Isis successfully wakes up her hungover half brother Zebediah by the graduated series of containers method. First the sleeper is drenched with a thimbleful of water, which is followed by the contents of an egg cup, a tea cup, a pint glass and finally a bucket.

Live-Action TV

A flashback in the Torchwood episode "Fragments". With Captain Jack and a "couple" of Victorian-era Torchwood members.
The Twilight Zone TOS episode "Two". After the man knocks out the woman, he wakes her up by dumping water on her.
Heroes
- In the final episode, chapter 3, Ando gives himself the ability to amplify other abilities after injecting himself with the serum. This causes him to black out, and he is subsequently awoken by Matt, who pours a glass of water on his face.
- Early on in Season 2, The half-naked, bloodied, tied-to-a-chair Peter is awoken with a bucket of the wet stuff to the face by the Irish gangsters who are holding him captive.
Band of Brothers. Major Winters uses this to wake up his alcoholic friend Captain Nixon. Unfortunately it turns out that Nixon had used the "water" jug for toilet purposes during the night (yes, that did happen in Real Life as well).
In El Chavo del Ocho, each time the title character gets scared he immediately paralyzes—after adopting an awkward pose nicknamed "la garrotera". The only way to snap off from this is by splashing water on him. Normally a small splash in his face works, but meaner-spirited characters often empty whole buckets on the poor kid.
This happened to Fraser on Due South in the Season 2 episode "Red, White or Blue".

Video Games

Volgin does this to Snake in Metal Gear Solid 3: Snake Eater, both to rouse him from unconsciousness and to get Snake all nice and conductive for the Electric Torture Volgin has in store.

Web Comics

Order of the Stick has O-Chul being woken up by a bucket of water for his daily torture.
Beeman is awakened this way in his background story in The Adventures of Dr. McNinja.
In Gastrophobia, Gastro wakes up his mother Phobia this way... because he can't sleep and want her to tell him a story. She's understandably ticked off, and gives him first a good spanking.

Western Animation

On Jimmy Two-Shoes, Samy tries this on Heloise, but it only succeeds in causing her to dream about being a mermaid.
Done in Beavis and Butthead: Do America when Muddy threw water at the two boys who passed out in the desert after the Disney Acid Sequence.
Subverted at the end of The Hunchback of Notre Dame where Esmeralda's Disney Death was brought forth by Quasimodo attempting to make her drink water with a spoon after she has passed out, but she does not drink it.
In The Perils of Penelope Pitstop episode "The Boardwalk Booby Trap", Pockets throws water on Snoozy when the latter is driving Chugga-Boom erratically.

Real Life

It should go without saying this works in real life. As non-aquatic animals, humans have a sensation when suddenly submerged or doused that makes them prepare to swim for their life to avoid drowning. This is why a cold shower (or a shower in general) works so well at waking people up.
This Prank. (WARNING: The video is NSFW due to language.)