The film Boarding School Wars has Jake Winters invoke this by name in his Shut Up, Hannibal! moment during a paintball battle that decides which school's boys get to go to the dance with the girls. "Yeah, you're right, you're right. We're messed up. We've got problems. And you nailed me in the back of the head. Good one. Guess our ragtag bunch of misfits haven't got a chance against your obvious superiority. But hey - shouldn't you be guarding your flag?" George's eyes widen as he realizes the bulk of the opposing team deliberately lost to separate the team from its flag. Using the walkie-talkies he smuggled in, George tries to tell his fellow team members what's happening, but it's too late. They arrive after the battle's been decided in a one on one shootout between their leaders.
The Dirty Dozen. The team sent in to blow up the Nazi R&R chateau is made up entirely of men facing either execution or life sentences in military prisons. Except for Magotnote who is an out-and-out psycho, serial killer, though, most of them are implied to be not-such-bad guys who simply were pushed too far, or never should have been allowed in the military at all.
In The Devil's Brigade, the Americans are an example, while the Canadians are more serious about it. The real First Special Service Force recruited its American members by asking for volunteers, not forcing the dregs of the Army into it, though plenty of troublemakers got "volunteered" by their commanding officers to get rid of them. The SSF weeded out a lot of the worst, but it was still a pretty motley bunch.
Armageddon: "The fate of the planet is in the hands of a bunch of retards I wouldn't trust with a potato gun."
The Massachusetts 54th Infantry, a regiment of black soldiers in The American Civil War, as seen in Glory. They include a gravedigger, an escaped slave who's as dangerous to himself as anybody else, an erudite Bostonian who's a piss-poor soldier, a stutterer who can't read, and the vast majority don't know either the alphabet, or even right from left. Their excellent performance in battle was a testament to their own heart and the training of their white commanders.
The crew of the USS Stingray in Down Periscope is the Ragtag Bunch of Misfits played for comedy. In this case, they are assembled by an Admiral with a grudge against the Stingray's captain intending them to fail an exercise the Stingray was participating in. The crew of the Stingray includes a captain with a tattoo on his penis, a jittery Number Two with No Indoor Voice, a female diving officer (actually, the most normal of the group - the offbeat part is that at the time of the film women didn't serve on US Navy submarines, and she's there as a test case), a washed-out basketball player, a compulsive gambler, a sonar technician with a ridiculously good hearing (he knows what eating an Oreo sounds like), a cook with few cooking skills and noxious flatulence, an admiral's son who wants to get kicked off the boat, an electrician who ignores simple safety instructions, and a crazy old mechanic who pours scotch into the engine to boost its power.
Shaolin Soccer provides an interesting twist with a rag-tag soccer team full of washed-up Shaolin monks. Despite their shabby appearance and total lack of soccer experience, they harness martial arts superpowers to defeat the reigning champions.
Major League is basically The Bad News Bears with a Major League team. Also, unlike the Bears, the Indians win the AL East. In this case, the team was put together specifically to lose, because the owner wanted to move the team and an abysmal season would justify it. The team starts gelling when they find out about this plan and decide they want to be winners.
Dodgeball: A True Underdog Story actually calls the team of average Joes "The Average Joes". They're made up of an apathetic gym owner, a man who thinks he's a pirate, a high school loser who wants to be a cheerleader to impress a girl (think about that one for a second), a man who thinks his mail-order bride loves him, and two of the gym employees who consider the gym better than their previous job at the airport. The only normal person on their team is a female lawyer (who happens to be bi). They are led by a paraplegic coach who loves throwing heavy objects at his players and making them dodge highway traffic.
WALL•E has the titular character (a trash compactor), his girlfriend (a heavily-armed survey robot) and a bunch of insane broken robots, HANS in particular.
In The Last Castle, a convicted army general gathers up an army of inmates at a military jail. One would think his army is a Ragtag Bunch Of Misfits, but since they all used to be soldiers, they're as disciplined and well-coordinated as any official battalion.
The replacement Washington Sentinels in The Replacements, featuring a notoriously easy-to-neutralize quarterback, a convict, an gambling addicted ex-soccer player, a sumo wrestler, two gargantuan gun-toting brothers, an outspoken Evangelical Christian with a bad knee, a deaf man, and a riot cop with serious anger management problems. Even the Sentinels' cheerleaders are a collection of bizarre performers who would never work on any other squad but pull it together for awesomeness.
Colette from Ratatouille describes her fellow chefs as such.
The 2009 Star Trek's reimagining of the characters verges on this: Kirk's under disciplinary review and not even supposed to be on board any ship, let alone commanding one; Scotty's been Reassigned to Antarctica; Sulu's a last-minute rookie replacement for the real pilot, who got sick. And after Nero wipes out the entire rest of the fleet, It's All Up To Them.
Caveman, the protagonist Atouk along his friend Lar, after being banished from their tribe they found their own when encountering other misfits wondering the wilds, including the old blind man Gog, the comely Tala, a gay caveman couple, the Asiatic caveman Nook (who inexplicably, speaks only in English), and a caveman midget.
The American team in Broken Lizard's Beerfest. To give you an idea, one of their members is a homeless male prostitute.
"There's no use waiting for the cavalry, because as of this moment, the cavalry is us. This is our fight, whether we like it or not. Just we few. We're not your classic superheroes. We're not the favorites. We're the other guys. We're the guys nobody ever bets on."
The core protagonists of Star Wars are a ragtag bunch of misfits In Space. Farmboy Luke, princess Leia, retired Jedi Ben, smuggler Han, fuzzball Chewie, prissy C3P0, and spunky R2D2.
In Vertical Limit, the crew assembled to go rescue the stranded climbers looks like this from the outside. A half-crazy mountain man, two slacker brothers, a woman mostly in it for the money… Subverted in that they’re all actually experienced climbers who know what they’re doing, and are crazy enough/desperate enough to mount what even they admit is a suicide mission.
The '70s cult comedy Steelyard Blues centers around a group of this type.
In a rare non battle/sports example, the groomsmen from I Love You Man consist of a the groom's father, brother, a few guys he went on "man dates" with,...and Lou Ferrigno.
The Avengers is pretty much "Ragtag Bunch of Misfits: Superhero Edition". A billionaire celebrity technological genius, a super-soldier who has been preserved in ice since WWII, a guy with incredibly destructive Jekyll & Hyde problems who's on the run from the military, a 900-year-old alien king-slash-demigod with a spectacularly dysfunctional family life, a trained-from-birth ex-Russian assassin who used to be a villain, and another ex-assassin turned highly eccentric government agent who spends half the film Brainwashed and Crazy. Now, put them all in close-quarters under high stress on a high-tech secret government airship with the demigod's insane, world-conquering little brother, and stir.
The Bellas from Pitch Perfect consist of a wannabe producer who was forced to join who wants to change things up, a By The BookIce Queen, an Ambiguously Gay girl with vocal nodules, an overweight Australian, a Butch Lesbian, a girl who constantly speaks in a whisper and says very disturbing things, and a nymphomaniac.
The Dwarves in The Hobbit. Only a few of them are actually warriors, while others range from miners to toymakers. In combat, their abilities could range from easily cutting through tough foes to ineffectively shooting at an enemy with a slingshot. Thorin, for his part, would take the group he has over a thousand trained soldiers every time — because when he called, they answered.
A ragtag bunch of street trash attempt a safe-crack in Welcome To Collinwood. Subverted in that these losers do lose (apart from the character Riley, played by William H. Macy, who luckily achieves his admittedly modest aims). Remake of the Italian movie I Soliti Ignoti (1958).
Okwe (Chiwetel Ejiofor) assembles a motley group of immigrants (a mortuary assistant, a hotel doorman, a sweatshop worker, a Hooker with a Heart of Gold) to get the best of the unpleasant Sneaky Juan in Stephen Frears' Dirty Pretty Things.
The Continental Army in The Crossing. While this trope is certainly the popular view of The American Revolution, the film defines "ragtag" as "hungry, wet, sick, and thoroughly demoralized" after numerous defeats. General Gates even points to the ragtag-ness in his criticism of Washington's plan because they are thoroughly not soldierly, unlike the Hessians. (They win anyway.)
How the CIA (and, for that matter, Charles and Moira) view the first generation of young X-Men in X-Men: First Class.