Fame is a funny thing: one day you're the biggest star in town, and the next day you're a nobody.
But years later, some stars manage to rise from the ashes to become Hollywood royalty again.
There's almost no way to guess if a scandal will be the end of a celebrity's career, or just the beginning of their comeback.
As you'll learn, Hollywood has forgiven bad behavior and awful crimes, but some stars are still in the doghouse.
FORGIVEN - Tim Allen
He was one of Hollywood's most popular TV actors in the '90s, but before he was famous the Home Improvement star lead a checkered life.
In 1978, Allen was arrested at an airport in Kalamazoo, Michigan for possession of cocaine.
Because of the size of his drug bundle - 1.4 pounds - Allen was slapped with drug trafficking charges and spent two years behind bars.
But according to Allen the drug charges, and his 1997 DUI arrest, didn't hurt his acting career.
"It put me in a position of great humility," he told Closer about his time behind bars.
"And I was able to make amends to friends and family and refocus my life on setting and achieving goals."
Allen insists he's been sober for more than two decades.
NOT FORGIVEN - Linsday Lohan
Lohan was a child star made famous by her roles in classic Disney movies like The Parent Trap.
But as she got older, the Mean Girls star fell in with a bad crowd.
After a bad breakup with her boyfriend, That '70s Show star Wilmer Valderrama, Lohan became famous for her drunken antics, including a number of car accidents.
The troubled star went through a vicious cycle - bouncing from DUI arrests to probation violations and jail time - before making things worse by shoplifting a necklace.
Despite staying on the straight-and-narrow for the last few years, Lohan's party girl image has stuck with her, and acting jobs are few and far between.
FORGIVEN - Martha Stewart
The queen of cookbooks is as popular today as she was when Martha Stewart Living first hit magazine racks in 1990.
In fact her latest TV show, featuring Snoop Dogg, has been getting rave reviews.
So it's easy to forget that Stewart did hard time for an insider trading charge in 2007.
Stewart was found guilty of avoiding a $45,000 loss by selling stocks thanks to an illegal tip.
After paying more than $200,000 in fines and penalties, Stewart spent seven months in federal prison.
Nicknamed "M Diddy" by her fellow inmates, Stewart made a seamless return to life as a celebrity chef once her time behind bars was over.
NOT FORGIVEN - Kevin Spacey
With two Oscars, a Tony Award and even a Grammy, it seemed like Kevin Spacey had a perfect career.
But the House of Cards star's life fell apart in days after actor Anthony Rapp accused spacey of making a sexual advance on him as a teenager.
Spacey's apology, which was widely criticized, only drew more accusations about Spacey's inappropriate behavior towards young men.
The actor's multiple film projects raced to replace him:
- Spacey was cut out of the final season of his Netflix show House of Cards.
- His scenes in All the Money in the World were re-filmed with Christopher Plummer.
- And a biopic of Gore Vidal starring Spacey was canceled.
The disgraced actor said he would seek "evaluation and treatment," days after the allegations broke, and hasn't been heard from since.
FORGIVEN - Dog the Bounty Hunter
If you ever watched Dog the Bounty Hunter, then you know that the famous bail bondsman loves to lecture the fugitive he captures.
But Dog - whose real name is Duane Chapman - hasn't always been on the right side of the law.
As a teenager, Chapman was associated with the infamous Devils Diciples motorcycle club.
He also spent time in prison for a first-degree murder charge, which lead to his career as a bounty hunter.
Chapman had been waiting in a car while his friend shot a drug dealer during a botched sale.
After 18 months behind bars, Chapman resorted to bounty hunting to pay down his child support bills.
The rest is TV history, but Chapman insists his redemption story proves no one is beyond help.
NOT FORGIVEN - Michael Richards
Richards won an Emmy award for playing Kramer, the fast-talking, wide-eyed neighbor on Seinfeld.
Like his co-stars, Richards' career struggled once the hit show ended.
His own TV series, The Michael Richards Show, lasted just one season.
The funnyman returned to his roots, becoming a stand-up comic, but cracked under pressure at an infamous 2006 show.
An audience member filmed Richards on his cell phone as the comic ranted and shouted racial slurs.
Since the disastrous incident, and his embarrassing apology, Richards has only appeared in a handful of guest roles and one failed sitcom.
FORGIVEN - Sean Penn
Today Penn is a film star and bestselling writer, while almost no one remembers the scandal that marked his career in the '80s.
At the time, the Fast Times at Ridgemont High star was married to pop musician Madonna.
The notoriously hot-tempered Penn got himself in trouble multiple times for lashing out at reporters, before allegedly turning his anger on Madonna.
A police report allegedly filed by the singer claimed that Penn had tied her to a chair and beaten her.
For what it's worth, press reports from 1989 say that Madonna later dropped the charges, and the singer herself said they were "outrageous" and "false" in 2015.
All we know for sure about the rumored incident is that the estranged couple divorced soon after.
But for some movie fans, that's enough to wonder why Penn's career is still going strong.
NOT FORGIVEN - Charlie Sheen
His role as the hard-drinking playboy Charlie Haper on Two and a Half Men earned him $1.8 million an episode.
But Sheen's outrageous behavior in real life has made him a Hollywood laughingstock.
After attempting to go sober three times in 2011, Sheen was fired from the sitcom for insulting its creator.
That lead to his infamous "meltdown" interviewer, where Sheen bragged about drug abuse and claimed he had "tiger blood."
Since then, Sheen's behavior has only gotten weirder.
The actor shares his home with a rotating cast of "goddesses" including former models, and revealed he was HIV positive in 2015.
The publicity from his firing earned Sheen a leading role in Anger Management, but since the series ended in 2014 he's basically been out of work.
FORGIVEN - Mike Tyson
Plenty of athletes have run-ins with the law, but Tyson's shameful behavior sets him apart.
The heavyweight boxing champion was arrested and charged with raping beauty queen Desiree Washington in 1991.
Tyson's jury deliberated for just 10 hours before convicting him, and he was sentenced to six years in prison.
Not only was Tyson released in just three years, but he spent his sentence in a youth center despite being 25.
After his release, Tyson staged a successful boxing comeback.
Then, he used his celebrity to star in comedy films like The Hangover, and a nature series on Animal Planet.
Today, the only lasting effect on Tyson's career from the case is his status as a sex offender.
NOT FORGIVEN - Bill Cosby
Throughout his long career as a stand-up comic and TV actor, Cosby was plagued by sexual assault allegations.
Cosby's wholesome image as a family man on The Cosby Show helped to cover up the charges, until they were brought to light again in 2014.
Since then, dozens of women have stepped forward to claim Cosby sexually assaulted them. And many share eerily similar stories.
The actor maintained his innocence even as criminal and civil charges against him piled up, saying, "people shouldn't have to go through that and shouldn't answer to innuendos."
But so far Cosby's accusers have had the last laugh: he was found guilty of three assault charges against basketball player Andrea Constand.
Cosby broke down and ranted in court after hearing the verdict, but the 80-year-old is still facing plenty more charges.
FORGIVEN - Matthew Broderick
His role as Ferris Bueller made Broderick one of the biggest stars of the '80s, but his career has a dark mark that is rarely mentioned today.
In 1987, Broderick was dating his Day Off co-star Jennifer Grey.
Just before Grey was set to promote Dirty Dancing, the celebrity couple took a vacation in Northern Ireland.
Broderick was touring the island in a rented BMW when he became lost in the rain, and likely started driving on the wrong side of the road.
The actor crashed head-on into another car, killing both of its passengers.
Broderick and Grey both escaped with only minor injuries, and the actor got another lucky break by avoiding jail time for the crash.
He reportedly paid just $175 for a careless driving charge, and has since avoided speaking to the victim's families.
"Of course you wonder if he got off lightly because of who he was," said Martin Doherty, whose mother and sister died in the crash.
"He got the same punishment he would have got if he'd run over cattle."
NOT FORGIVEN - Gwyneth Paltrow
While she keeps her nose clean and has never been in trouble with the law, Paltrow still ranks among the most hated celebrities in Hollywood.
Paltrow still gets good reviews for her acting career in films like Iron Man, but her business project Goop attracts plenty of controversy.
The wellness brand promises to "nourish the inner aspect," but critics say it sells overpriced junk.
Goop products have included jade eggs, coffee enemas, psychic vampire repellent, and stickers that "rebalance" the body's "energy frequency."
Despite all of the bad press Paltrow's project gets, Goop is a global brand, and still selling plenty of vampire repellent.
FORGIVEN - Robert Downey Jr.
Unlike his co-star Gwyneth Paltrow, fans are very happy to overlook the Iron Man actor's life off-screen.
Between 1996 and 2001, Downey faced on drug possession charge after another, and was fired from the set of Ally McBeal for his addiction.
Downey claimed he had been a drug addict since he was just eight years old, after learning the habit from his father.
At his lowest point, Downey was charged with drug and gun possession, released on parole, and arrested a month later for trespassing while high on drugs.
"It's like I have a shotgun in my mouth," the actor famously told a judge, "and I've got my finger on the trigger, and I like the taste of the gun metal."
Finally, a 2001 stay in a drug rehab facility stuck, and Downey has been sober ever since.
NOT FORGIVEN - Richard Gere
The silver fox isn't known for bad behavior, but he still insists he will "never act in Hollywood again."
He once landed leading roles in hits like An Officer and a Gentleman and Pretty Woman, but Gere's recent career has mainly included independent films.
In an interview with The Hollywood Reporter, Gere had a surprising theory about why he was "blacklisted."
As a world-famous Buddhist, Gere is a devoted supporter of the Dalai Lama.
He even spoke out against China's treatment of Tibet at the Academy Awards in 1993, calling it a "horrendous human rights situation."
Those remarks got Gere banned from China for life. Since his movies are also restricted in the world's single largest film market, big roles have dried up.
"I recently had an episode where someone said they could not finance a film with me because it would upset the Chinese," Gere explained.
FORGIVEN - Mark Wahlberg
Wahlberg has developed a squeaky-clean reputation as a devoted Catholic and a Hollywood action star, but he was a real terror in his youth.
Before he was a hip hop star or famous actor, Wahlberg was a teenage hooligan.
The actor admits he was hooked on cocaine and other drugs by age 13.
Years later, Wahlberg was charged for throwing rocks and shouting racial slurs at African-American children.
Then, at age 16, Wahlberg knocked a Vietnamese man unconscious with a stick, and blinded another Vietnamese man with a sucker punch later the same day,
Wahlberg was charged with attempted murder for the attacks, but spent just 45 days in jail.
The actor brought his troubled past to light in 2014, when he tried to have his convictions erased for business reasons.
After facing backlash from some of his victims, Wahlberg dropped the request.
NOT FORGIVEN - R. Kelly
After years of accusations, it seems like the R&B singer's career is finally facing repercussions for his allegedly shady behavior.
Kelly married the 15-year-old pop singer Aaliyah in 1994, before the underage marriage was annulled.
In the decades since, multiple women have accused Kelly of acting inappropriately towards them as teenagers.
The singer settled the many charges against him out of court.
More recently, three sets of parents alleged that Kelly was keeping their daughters in an abusive cult.
After 24 years of rumors and claims, Kelly's inner circle are finally jumping ship - his former lawyer, assistant, and representative have all distanced themselves from him.
Only time will tell if the latest charges actually stick to Kelly.
FORGIVEN - Ice T.
While he plays a detective on Law and Order: SVU today, in real life Ice T. has not always been a model citizen.
The rapper - whose real name is Tracy Marrow - claims that as a teenager he used his father's Social Security credit to buy a flophouse apartment.
Marrow sold marijuana and stolen car stereos out of the apartment before joining the army.
After leaving the armed forces, Marrow claims he worked as a pimp and a bank robber.
Ironically, Marrow got in more trouble over the lyrics of his gangster rap songs - including "Cop Killer" - than he ever did for his actual crimes.
NOT FORGIVEN - Mel Gibson
Whether or not the Braveheart director is back in Hollywood's good graces is debatable.
But there's no denying that he's still a controversial figure.
Gibson's fall from grace started in 2006, when the longtime alcoholic was pulled over by police for driving under the influence.
The actor launched into a profane and anti-Semitic rant that became headline news when the arrest report went public.
Gibson immediately entered a rehab program, but stuck his foot in his mouth again in 2010, when racist and abusive phone messages to his ex-girlfriend were leaked.
After leaving the spotlight for years, Gibson returned to the director chair after Robert Downey Jr. and other close friends asked for his forgiveness.
Time will tell if Gibson has changed his ways, but he's planning a big comeback with a Passion of the Christ sequel.
FORGIVEN - Christian Slater
With roles on hit shows like The West Wing and Mr. Robot, Slater is one of the most in-demand actors on both the big and small screen.
But the leading man has a long history of outrageous behavior that stretches back to the late '80s.
Slater spent 10 days in jail in 1989 after being arrested for drunk driving and assault.
He landed in even more trouble after trying to board a flight with a gun in his luggage.
Slater also has a troubled history with women too, including his ex-girlfriend Michelle Jonas. He was charged with assaulting Jonas and a police officer while high and drunk in 1997.
The actor spent three months in jail and more than six months in rehab for his bad behavior.
But he obviously didn't learn his lesson, because Slater was arrested for sexually harassing a woman on the street in 2005.
Charged were dropped as long as Slater stayed out of trouble for six months, and he's kept his nose clean ever since.
NOT FORGIVEN - O.J. Simpson
Not only was the NFL running back one of America's most popular pro athletes during his heyday, but he was also a movie star.
Comic roles in movies like The Naked Gun, and more serious blockbusters like The Towering Inferno made "the Juice" a household name.
But Simpson's fame turned to infamy in 1994, when his estranged wife Nicole Brown and her friend Ron Goldman were murdered.
America tuned in to every moment of the "trial of the century," from the dramatic white Bronco car chase, to the climactic moment when O.J. pulled on the gloves.
Of course, the star athlete was found not guilty, but his career in Hollywood was basically over.
Simpson resorted to hosting prank shows like Juiced before being sent to jail in 2008 for taking part in an armed robbery.
Now a free man again, Simpson says he has no plans to return to acting, and just wants to enjoy his privacy.
And after Simpson's public confession aired earlier this year, he shouldn't expect too many job offers.
For more bad behavior, check out the 10 Celebrities Who Have Admitted to Cheating on Their Partners.
Child stars get in trouble too, and here are 8 Young Celebrities We Grew Up Watching Who Ended Up Behind Bars.