Characters (adolescent or young adults, usually) get together to do something manifestly dumb and often prohibited, but hey, they're young and so immortal, aren't they? The hold-outs are often persuaded because they don't want to look like a Dirty Coward, and often one of the bolder characters urges it's Not Cheating Unless You Get Caught. Visiting an abandoned house or performing a ritual are common. Bullying a Dragon can be a form of it; you're not afraid of him just because he can warp space-and-time with his thoughts! The Call Receival Area and the Forbidden Zone are popular destinations. A particularly idiotic Wild Teen Party may feature one, especially if the participients got very, very drunk.
Occasionally performed by a solitary figure (but even then he often bragged about it beforehand).
Popular Horror Trope. Often makes them Too Dumb to Live. "Hey everyone, we should so go to the abandoned camp ground where dozens have been slaughtered in the last year and have a party with bad music and alcohol! Afterwards, we'll all split up and have sex!!"
Compare Kimodameshi. Scare Dare involves even younger characters, children, and is much less likely to be dangerous; and Straying Baby a character younger still, who really is oblivious.
Contrast Deadly Prank, where someone else is imperiled. If whatever they do ends up backfiring and yet they get out of it without a scratch, then it's No One Should Survive That.
Note: does not cover shows that set challenges; this is something the characters dream up of their own stupidity.
Because this is often times Truth in Television, no need for Real Life examples.
"This year, 3 million young adults out there will get their drivers' license. Better get yourself a safe car."
Bruce Banner became The Hulk because Rick Jones accepted a dare to drive onto a nuclear testing site. To his credit, Rick has spent a good chunk of the rest of his life trying to make it up to Bruce as best he can.
In fairness, whilst heroic, Bruce's decision to run out onto a nuclear test site to save Rick was equally as suicidal.
Not an accurate rendition of the Hulk's origin: Bruce ordered the countdown stopped while he went out to get the kid off the field, but the person he gave the order to was actually a Russian spy who continued the countdown in the hopes that Bruce would get killed.
In Dan Abnett's Warhammer 40,000 novel Brothers of the Snake, Space Marines are forbidden to try a stunt, diving into a sea trench and leaving something. One young Marine does it, and has an older Marine come to ensure that he needs no help. Then, later, another tries, and the Marine who goes after him is only able to recover the corpse.
In Lee Lightner's Warhammer 40,000Space Wolf novel Sons of Fenris, Lieutenant Paulinus tries to remember his travels in the city in his younger days. He was ashamed of them — "callow youths looking for cheap thrills" — but now, he needs to lead his men in those sections.
The fake terrorists from Larry Niven and Pournelle's book Oath of Fealty are in a word, idiots, and have almost no survival instinct whatsoever.
Older Than Print: In Beowulf, the titular hero describes his and his cousin's swimming across the sea as something they did when they were young and prideful.
In Sandy Mitchell's Cain's Last Stand, Ciaphas Cain observes that Kayla has too much sense to keep up with Jurgen's crazy driving, despite the delusions of immortality that youth gives.
In a Warrior CatsExpanded Universe story, a bunch of RiverClan apprentices and young warriors repeatedly do stupid stunts, such as deciding to jump off a cliff for fun, or having a "who can fall out of a tree the hardest" contest. Eventually, a RiverClan cat convinces them to grow up, by having them sit a vigil.
In Robin McKinley's Sunshine, youngsters sometimes gang together to see if they can spot a vampire. Sunshine did it herself, and her little brother Kenny might be doing it.
Dave Barry Slept Here explains in the introduction why young people are too dumb to know their country's history:
Young people have always been stupid, dating back to when you were a young person (1971-1973) and you drank an entire quart of Midnight Surprise Fruit Wine and Dessert Topping and threw up in your best friend's father's elaborate saltwater aquarium containing $6,500 worth of rare and, as it turned out, extremely delicate fish. (You thought we didn't know about that? We know everything. We are a history book.)
Edenborn has Deuce and Penny, who steal a Cool Plane, ransack pantries and wine cellars across Europe for victuals, and realize they're in way over their head with their parents.
In the episode The Dominators, Cully and his friends arrive on the island without permits, for thrills. It makes it hard for him to persuade anyone after the others get killed.
Virtually all the teenage characters in Twin Peaks are so dumb it's almost painful to watch. From Bobby trying to scam Ben Horne to Shelly offering live-in care to her comatose Ax-Crazy ex-boyfriend Leo (on Bobby's advice) to cash in on insurance checks to James...well, anything James does, ever, it's a wonder anyone ever reaches old age in this town.
For all the intelligence shown by the younger generation on Terra Nova, it might as well be Twin PeaksIN SPACE!. Favorite pastimes include making out in the raptor-infested jungle, among other idiotic pursuits.
Teenagers and young adults did many, many stupid things over the course of Veronica Mars, from vehicular manslaughter to accidental arson to assault and even rape. Many of the kids depicted doing these things weren't even stupid; it was Truth in Television in that a young person's decision-making skills are prone to be compromised by a number of things, including hormones, substance abuse and lack of life experience.
In many productions of Romeo and Juliet, the fights that break out among the young men in the feuding houses are guilty of this. The only cool heads among them, Romeo and Benvolio, get called out on being scared to fight.
The premise of Shivers is that you get locked in an abandoned haunted museum on a dare.
In The Woods Are Dark six Irish teenagers decided it'd be a great lark to visit the home where a local boy had murdered his entire family. Despite the fact that one of them disappeared and another was found white-haired and gibbering a few days afterwards, five years later the four remaining idiots actually decided to go back.
In Sinfest, one drone taunts another into diving through traffic.
Bumblebee in Transformers Animated might not technically be a kid (as far as we can tell), but he's got the mind of one and does equivalent stupid stuff. The most notable might be his upgrading himself with illegal and dangerous boosters and sneaking out onto an underground racing circuit with Sari.
An early episode of Gravity Falls involves Wendy and her friends visiting an abandoned convenience store haunted by a reality warping elderly couple with a homicidal grudge against teenagers. They only survived because the ghosts were willing to negotiate with 12-year-old Dipper (technically not a teen).