"I'm being judged by 12 people too dumb to get out of jury duty!"
A jury defies all logic and common sense and comes back with verdict contrary to the evidence. It's not a Joker Jury, Jury of the Damned or a Kangaroo Court — a group of regular citizens has come back with the wrong decision.
Usually, a not-guilty verdict is intended to demonstrate the jury's outright gullibility (or intimidation), whereas an unfair guilty verdict indicates they were unable to see past some fear or prejudice against the defendant.
In real life (principally in the USA) the "voir dire" process is meant to ensure that juries are made up of fair and impartial members who will treat the case seriously. In the UK and Commonwealth, it can include testing the competency of potential jurors. Still, a number of high-profile cases with unexpected outcomes have led to juries being described as "twelve people too stupid to get out of jury duty."
Occasionally, a surprise acquittal can be due to a phenomenon known as "jury nullification", in which the jurors return a "not guilty" verdict even though the prosecution has in fact proven their case. This is usually because the jury feels that extenuating circumstances justify the crime, or occasionally because they feel the law is unfairly applied or simply wrong. There are two sides to this: A) The US legal system says that it is not the jury's place to decide what the law should be, but to come to a conclusion as to whether the law as it is currently written has or has not been broken. B) Nevertheless, jury nullification is legal in the US. A criminal court can't insist on a verdict, an acquittal can't be appealed, and jurors can't be punished for a verdict. note There are circumstances where a judge can set aside an acquittal, but it's extremely rare and limited to cases of juror misconduct; the result is a mistrial, not a guilty verdict
The Great White Shark was dumb enough to have his case transferred to Gotham City to skate on an Insanity Defense for embezzling millions from the life savings of his company's clients; dumb, because he winds up getting sent to Arkham Asylum. The presiding judge lampshades the jury's idiocy for falling for his obvious lies, but takes comfort in knowing the white-collar "Shark" will be a mere guppy amongst the myriad of maniacs and psychopaths that Arkham houses.
Liar Liar has Fletcher's secretary relate a friend's story of the "burglar sues the homeowner after B&E goes bad and wins" predicament to point out how he and other Amoral Attorneysare all alike. Fletcher insists he's not: if he were the burglar's attorney, he would've gotten her friend for twice the money she lost.
Mystery Alaska has an incident where a local store owner is acquitted in the shooting of the representative of a Walmart expy who wanted to buy his store. Since he's local and the best hockey player in town, the jury finds him not guilty so he can participate in the Big Game against the NY Rangers. They also attempt to award him damages, but the judge rightly points out you can't do that in a criminal trial. He also lambasts the jury for putting the game above what's right. No one really cares.
Finch: You think your average juror is King Solomon? No! He's a roofer with a mortgage. He wants to go home and sit in his Barcalounger and let the cable TV wash over him. And this man doesn't give a single, solitary droplet of shit about truth, justice or your American way. Rohr: They're people, Fitch. Finch:My point, exactly.
In To Kill a Mockingbird, Atticus Finch demonstrates the accuser Mayella's injuries were caused by a left-handed individual while the defendant, Tom Robinson paralyzed his left arm in an accident. The jury of that time in the Deep South still convicted him, refusing to consider the idea that a black person could ever be Wrongly Accused of a crime.
Due to the political stances of half the court, the court-martial of Pavel Young in Field of Dishonor refused to convict him of any of the charges that would have gotten him executed, even though their logic for doing so was explicitly declared invalid by standing court rulings. The aftermath of this caused the plot of the second half of the book.
A frequent occurrence on Law & Order. In "Blue Bamboo" (S5-3), a woman stalked and killed the Japanese businessman who pimped her out as a sex slave to his clients. Her lawyer argued Battered Woman Syndrome but the prosecution proved her testimony was plagiarized from textbooks on Battered Woman Syndrome and since she was no longer in Japan (and thus completely free from the victim's grasp), her murder was revenge-motivated. The judge instructs the jury not to consider the Japanese's somewhat misogynistic culture in their verdict, but they acquit her anyway.
On The Practice a drug dealer claimed self defense in stabbing (7 times) an addict he'd threatened to murder over his mounting drug debts. His long criminal record and the complete lack of any supporting evidence prompt him to try and strangle the DA in open court in an unsuccessful bid to provoke a mistrial and delay the inevitable (the judge even refuses to grant it because he knows the guy's going down for murder). The not guilty verdict prompts the DA to break down into a tirade about juror stupidity.
Another episode features the judge berating the jury for their decision to award a ridiculous amount of money to the plaintiff in a dubious fraud lawsuit, before exercising his power to reduce the amount.
Jimmy once defended his cousin for firing a woman due to her Iranian heritage. His case literally amounted to, "she's a good person, but we should judge her for the actions of her countrymen". It works. The judge throws out the verdict, orders Jimmy's cousin to pay a hefty compensation, and delivers a "The Reason You Suck" Speech to Jimmy, his cousin and the jury.
Jimmy once defended a woman who stabbed a drug lord to death and the judge wouldn't allow them to plead self defense or defense of others. He managed to convince the jury to acquit.
The jury for Clay Davis's trial in The Wire, who are seemingly under the impression that massive campaign finance fraud ceases to be illegal if you give away all the money.
Note of course that Davis actually wasn't giving the money away, and was just as massively corrupt at the prosecution claimed; it's just that the jury were too dumb to see through his fairly wild - if articulate - lies of apparently handing it out by the pocketful to passing people in need.
Blackadder Goes Forth, while we don't know the details of the case, presents us with a nice example:
Blackadder: "I remember Massingbird's most famous case: the Case of the Bloody Knife. A man was found next to a murdered body. He had the knife in his hand, 13 witnesses had seen him stab the victim, and when the police arrived, he said "I'm glad I killed the bastard." Massingbird not only got him off; he got him knighted in the New Year's Honours List and the relatives of the victim had to pay to have the blood washed out of his jacket!".
The second episode of Harry's Law featured a woman on trial for committing armed robbery, with eyewitness testimony and video evidence. The defense Harry presented basically amounted to "Yeah, she did it, and she wasn't insane or senile, but she's an old woman". It worked. With only slightly more justification, the first episode had a young man get off on drug possession charges (and a corresponding "third strike" prison sentence) through the argument that as he was on his way to college, the "greater good" of society would be better served by not convicting.
In the Sherlock episode "The Reichenbach Fall" Moriarty stands trial for attempting to steal the Crown Jewels. He was caught red-handed at the scene, there are plenty of witnesses and good quality security camera footage. At trial he offers no defense and the judge tells the jury that they have no choice but to convict. They return a unanimous verdict of 'not guilty'. Moriarty threatened to kill the jurors' families unless they acquitted him
JAG: Basically the plot of the season ten episode "The Sixth Juror" when Petty Officer Jennifer Coates is brought in as juror and starts asking pertinent questions which no one had thought about.
An episode of How I Met Your Mother involves environmental lawyer Marshall Erikson in court against a corrupt Mega Corp. for illegal dumping which resulted in an ecological nightmare in a particular lake. In a variation of this trope, he actually convinces the jury and they find the corporation guilty; but then the judge decides to all but waive the fines and any other consequences (from $25 million and jail time for the executives who knowingly polluted the lake down to a measly fine of $25 thousand) because the company is big and powerful and it was just some stupid lake.
Rumpole of the Bailey presents us with "Rumpole a la Carte," in which the chef at a posh French restaurant in London is on trial for a health violation—namely having a live mouse presented upon a customer's plate. Like most things in the health code this is a strict-liability offense: it doesn't matter why you did it, it only matters that the code was violated. However, Rumpole does his best to laugh the case out of court, and produces evidence that the mouse was planted as a complex plot by the cashier.note The chef's venomous French wife was divorcing him, and since they had been married under French law, she would get half of the profits from the restaurant via community of property. The cashier hated the wife and was desperately in love with the chef, so she cooked up the scheme to ruin the restaurant so the ex would get nothing. The jury acquits.
The first television series of Dragnet featured an episode in which a jury acquitted a (guilty) man because a witness could not identify the man himself but only describe what he was wearing. They did this despite expert testimony that the probability of two people wearing identical outfits was very low. The 'not guilty' verdict prompts the Judge to lecture the jury on what idiots they are for a good five minutes. (The rest of the episode involved the police arresting him for a new crime with definite proof it was him.)
Twelve Incompetent Men (and Women!)note Yeah, a pun on 12 Angry Men by Ian Mc Wethy is a short play based entirely on this premise. They have footage of the defendant committing his crime on camera. He even shouts out his name in the footage. The play starts with a judge saying that if it took more than thirty minutes for the jury to deliberate, he would be very disappointed in them. Needless to say, the verdict came back innocent.
Played with in The Order of the Stick when Haley points out that the innocent verdict they receive when being tried for destroying a mystical Gate is erroneous because, regardless of the surrounding circumstances, they are actually guilty of the charge. It turns out that the entire trial was a sham orchestrated to get them to the city, and the "jury" was in fact Roy's father using an illusion.
In the Global Guardians PBEM Universe, it proved almost impossible to convict Ambrosia of any crime, even when she was caught red handed with both video and DNA evidence, because her lawyer managed to disqualify any woman who had a chance of landing on the jury. Her pheromone-driven power to cause all men to view her as attractive and friendly did the rest...
The Boondocksplays it for laughs. In one episode, an intern for the Black Panthers was sentenced to death for the murder of a cop despite the real killer leaving the gun with the receipt attached, his prints on the gun and shouting to everyone around that he was the murderer.
Uncle Ruckus served on a jury that convicted a blind black man accused of shooting (from 50 yards away) three white women with a rifle and delighted in shouting racist threats (complete with a hangman's noose) from his seat in the jury.
There was also the episode in which R. Kelly is acquitted of lewd conduct with a minor, despite overwhelming evidence, because the jury liked his music and Kelly's (white) attorney argued that the (black) prosecutor hates black people.