Sideshow: THE EX FACTOR

It's impossible to boil a year's worth of celeb news down to one word. So much happens! But for 2011, there was a theme: The Breakup. From Ashton Kutcher and Demi Moore to Arnold Schwarzenegger and Maria Shriver, the bonds that bind were unbound, hearts broken, scandals and extramarital orgies exposed - and divorces filed.

You don't have to be married - or even dating - to break up. Just ask Lindsay Lohan and Charlie Sheen, who in their own unique ways divorced that most constant of spouses, Reality Itself.

The aforementioned C-Sheen, who reportedly made $2 mil an episode as the star of TV's No. 1 comedy, Two and a Half Men, became a one-man big top after a series of allegedly alcohol-, drug- and sex-fueled scandals that made him a folk hero with 2 mil Twitter followers.

"I'm not bipolar, I'm bi-winning," he announced in  a webcast he beamed from the Sheenosphere in late February. The typically hyper Chas slammed TV shrink Dr. Drew Pinsky for opining that he suffered from bipolar mood disorder.

The webcast came at the height of a months-long crazy dreamboat ride of twisted notoriety and self-promotion. ("It's been a tsunami of media, and I've been riding it on a mercury surfboard.")

At last, the self-described Vatican Assassin Warlock was fired from Men and replaced by that other walking sex scandal, Ashton Kutcher.

The year's second-most-accomplished celeb train wreck had a banner year. LiLo, 25, did it all! Two tours in rehab for drug and alcohol abuse, not to mention house arrest (by all accounts a jolly, party-filled sojourn), a theft conviction, and two stints in jail.

Is this the adorable gal from The Parent Trap?

Well, LiLo has decided to turn a new leaf. She's working hard on her court-mandated community service job mopping up at the county morgue. She's even in therapy! And she made a bid for a comeback, posing for a nude photo feature in Playboy. Gotta admire her gumption.

Ashton Kutcher didn't just inherit Sheen's job. It seems he also acquired his penchant for orgiastic sex sessions.

Ashton was cute in That 70's Show, and cool, in that sinsemilla-sweet way, in Dude, Where's My Car? But the dude came into his own - as a serious thesp, technology expert, and high-tech corporate investor - only when he married Demi Moore in September 2005. He was 27, she 42 with an ex-husband (Bruce Willis) and three kids, Rumer, Scout, and Tallulah. Age didn't matter, he said.

All you need is love.

He showed just how much he dug his wife by spending their sixth wedding anniversary in the arms of party girl Sara Leal, 22, at a San Diego. hotel. Leal later said she was impressed by his stamina and sexual performance.

She helped him win the governor's mansion in Sacramento, Calif., for two terms. With that partnership over, and their four kids - Katherine, 22, Christina, 20, Patrick, 18, and Christopher, 14 - more or less grown up, there seemed little to keep Maria Shriver and Arnold Schwarzenegger together after 25 years. It all came crashing down with the revelation that Arnold had a fifth child, an illegitimate son named Joseph, sired 14 years earlier with Mildred Patricia "Patty" Baena, 50, a Guatemala-born woman who worked as a maid for Arnold and Maria for more than 20 years. Arnold said he wanted to wait until after he vacated the mansion to tell Maria.

Considerate? Calculating?

Just good politics, dear.

None of 2011's breakups quite reached Mel Gibson-Oksana Grigorieva levels of ugliness - except, perhaps, for the ongoing battle between Terrence Howard and his second wife, Michelle Ghent. Their 13-month marriage blew up in February, when she filed for divorce, claiming he beat her. Howard was slapped with a restraining order.

Howard, who has a manse in Lafayette Hill, this month countered with shocking claims of his own. Noting that he is black while Michelle is not, he said she regularly insulted him using racist epithets and threatened to have a Russian hit man kill him.

The quickie marriage has been a fixture of celebdom since Rudolph Valentino was dumped by Jean Acker on their wedding night in 1919.

But there's something more scandalous - it's borderline heinous - when it comes to Kim Kardashian's 72-day marriage to Kris Humphries.

Hyped in daily progress reports, the couple's Aug. 20 wedding was a televised $10 mil affair said to be one of the most expensive weddings in human history. It paid for itself: Kim 'n' Kris reportedly pocketed $17.8 mil from media deals.     No doubt that's why so many fans and gossipers were mad when Kim filed for divorce.

Sinéad O'Connor, 45, wrote on her website this week that not more than three hours had gone by after she said "I do" to her fourth hub, therapist Barry Herridge, Dec. 8 in Las Vegas when she knew it was over.

Their wedding night wasn't so much special as unusual - Sinéad went out trolling for drugs with Barry in tow. Barry is "a drugs counselor," she later told Britain's The Sun. "What was I thinking?"

The union lasted 16 days.

 Two NBA stars, both with vital links to Philly, went through the wringer this year: Lower Merion High School alum Kobe Bryant, 33, and 36-year-old former Sixers guard Allen Iverson.

Vanessa Bryant, 29, filed for divorce on Dec. 16 after 10 years, citing irreconcilable differences. She said she was sick of putting up with Kobe's serial philandering. Things have been civil, and the two have requested joint custody of their daughters, Natalia and Gianna.

It's been a bit more animated chez Allen and Tawanna Iverson. In June, Tawanna filed for divorce for the second time in 15 months, saying their 10-year marriage is "irretrievably broken." Earlier this month, Tawanna accused Allen of leaving her and their five kids without any financial support. The pair are awaiting a court date.

Jennifer Lopez, 42, and Marc Anthony, 43, shocked fans with their July announcement they were getting divorced after seven years. Things were amicable until last week. Us Weekly claims that Marc plans to fight for custody of the couple's 3-year-old twins, Max and Emma. Seems he was peeved when he saw pics of J-Lo frolicking with her 24-year-old boytoy Casper Smart.

Hugh Hefner, 85, got egg in the face in June when his highly publicized wedding to Playmate Crystal Harris collapsed. Harris, who is 60 years his junior, dumped Hef two days before the big day.

British comic Russell Brand, 36, on Friday revealed that rumors he and singer Katy Perry, 27, are getting divorced are true. "I'll always adore her and I know we'll remain friends," he said. Theirs also was a short marriage. They wed in October 2010 at a tiger preserve in India.