Rick Perry wasn't the only Republican candidate with an "oops" moment this year. Virtually all Republican candidates had their fair share of gaffes as well as bizarre confrontations.
Here's a look at the top campaign moments of 2011.
In what was undoubtedly the most embarrassing gaffe of his campaign -- if not his political career -- Texas Gov. Rick Perry drew an agonizingly long blank at a GOP debate in November, when he failed to name a third agency he said he would eliminate if he were to become president.
"It's three agencies of government when I get there that are gone ? Commerce, Education and the um, what's the third one there? Let's see. Oh five ? Commerce, Education and the um, um," Perry said at the debate sponsored by CNBC.
Mitt Romney, standing two podiums to Perry's right, offered the Environmental Protection Agency as a suggestion.
"EPA, there you go," Perry said. But then, the Texas governor quickly retracted his statement, saying the EPA doesn't need to be eliminated but simply rebuilt.
Again, he tried to name the third mystery agency.
"But you can't name the third one?" CNBC moderator John Harwood asked.
"The third agency of government I would do away with - the education, the uh, the commerce and let's see. I can't the third one. I can't. Sorry Oops."
Perry finally remembered the third agency 15 minutes later after referring to his notes, saying "By the way, it was the Department of Energy I was talking about."
The moment became the butt of many a jokes, including a Saturday Night Live skit.
An otherwise uneventful book signing in May by Newt Gingrich and his wife Callista became a not-so-shining moment for the two when a 24-year-old protester -- who famously became known as the glitter culprit -- dumped a box of glitter over the political couple.
"Feel the rainbow, Newt," Nick Espinosa said as he poured the box of glitter over the former Speaker's head. "Stop the hate. Stop anti-gay politics. It's dividing our country and it's not fixing our economy."
As Espinosa was escorted out of the room, Gingrich cleaned the glitter off the table and from his coat, saying "Nice to live in a free country."
This wasn't Espinosa's first protest against a politician. In July 2010, he dumped 2,000 pennies on Tom Emmer, a Republican candidate for governor of Minnesota, in protest of immigration policy.
To Mitt Romney, it may have been a seemingly innocent bet. In a debate sponsored by ABC News this month, the former Massachusetts governor bet his opponent Rick Perry $10,000 that that he does not and did not support a national individual mandate in his book.
"I read your first book and it said in there that your mandate in Massachusetts which should be the model for the country. And I know it came out of the reprint of the book. But, you know, I'm just sayin', you were for individual mandates, my friend," Perry told Romney.
"You know what? You've raised that before, Rick. And you're simply wrong," countered Romney.
"It was true then. It's true now," Perry quipped laughingly.
"Rick, I'll tell you what. 10,000 bucks -- $10,000 bet?" Romney responded to applause.
Romney's campaign insisted the wager was not a gaffe but it quickly catapulted into a public relations disaster for Romney, who was painted as out of touch with the American people by his opponents. The bet played right into his rivals' arguments that Romney is not a candidate who can relate to the middle-class or be entrusted to help the middle-class recover from the country's recession.
While campaigning in New Hampshire in early December, Mitt Romney had an unusual encounter with a gay veteran who questioned the former governor's stance on same-sex marriage.
Bob Garon was eating breakfast at a diner when he was joined by Romney, who was campaigning there.
The 63-year-old veteran questioned Romney on whether he supports the repeal of the New Hampshire same-sex marriage law, to which Romney replied: "I believe a marriage is between a man and a woman."
Garon, who is gay, continued to probe Romney.
"It's good to know how you feel, that you do not believe everyone is entitled to their constitutional rights," the New Hampshire resident said.
"No, actually I think at the time the Constitution was written it was pretty clear marriage was between a man and a woman," Romney replied, as he got up to leave.
Garon later voiced his anger to reporters at Romney's answer, saying, "I went and fought for my country and I think my spouse should be entitled to the same [benefits as they would] if I were married to a woman. What the hell is the difference?"
Herman Cain has a way with words. The former CEO of Godfather's Pizza invented such headline-grabbing phrases as "Ubeki-beki-beki-beki-Stan-stan" and "flavor of the month." But when it came to speaking his mind on President Obama's policy in Libya, the former businessman was speechless.
In an interview with the Milwaukee Journal-Sentinel's editorial board in November, Cain appeared to have a brain freeze when asked whether he agrees with Obama on Libya.
"Ok, Libya," Cain replied, followed by an awkward 10-second pause that the presidential candidate filled by looking down at the table and fidgeting with a bottle of water.
"President Obama supported the uprising, correct? President Obama called for the removal of Gadhafi?" Cain prodded reporters. "Just want to make sure we're talking about the same thing before I say, 'yes I agree, I know I didn't agree."
"I do not agree with the way he handled it for the following reason," Cain continued. "No, that's a different one."
More silence ensued.
Cain blamed it to an overflow of information inside his brain: "Got all this stuff twirling around in my head."
Though he staunchly denied multiple accusations of sexual harassment and a charge of a 13-year-long extramarital affair, Herman Cain couldn't recover from the political fallout of the scandal. As his campaign took a nosedive and donations began to drop, the Georgia resident decided to drop out of the race saying the "false accusations" had created a "cloud of doubt over me and my family."
"With a lot of prayer and soul searching, I am suspending my presidential campaign, because of the continued distraction, the continued hurt on me and my family," he said at a press conference in Atlanta, where he began his unusual campaign in May.
Cain told Barbara Walters in an interview earlier this month that it wasn't his wife who asked him to drop out, but that he made the decision because of the pain the news was causing his family.
A Republican audience loudly booed at a gay soldier who posed a question to Rick Santorum about the military's "Don't Ask, Don't Tell" policy at the GOP debate in September.
"In 2010, when I was deployed to Iraq, I had to lie about who I was, because I'm a gay soldier, and I didn't want to lose my job," said Stephen Hill, whose image was projected on a large TV screen in the debate hall. "My question is, under one of your presidencies, do you intend to circumvent the progress that's been made for gay and lesbian soldiers in the military?"
Santorum replied with a long, impassioned answer detailing his opposition to the controversial policy.
"It should not be an issue. Leave it alone, keep it... to yourself, whether you're a heterosexual or a homosexual," Santorum ended to wild applause and cheering.
But even though he may have disagreed with the soldier, Santorum criticized the hecklers in the debate hall.
"I condemn the people who booed that gay soldier," the former senator from Pennsylvania told reporters after the debate. "He's serving our country. I thank him for his service, and I hope he's safe and returns safely and does the mission well."
Ron Paul's views on cutting spending may be boosting his popularity but many of the Texas congressman's world views remain controversial. Case in point, Paul was the subject of loud booing in a September debate when he blamed U.S. policies on Palestine and having bases in Saudi Arabia as the cause of the Sept. 11 attacks.
Paul argued in his Texas Straight Talk column on the 10th anniversary of the attacks that foreign occupation is the "real motivation behind the September 11 attacks and the vast majority of other instances of suicide terrorism."
When asked to explain that viewpoint by rival Rick Santorum at the CNN/Tea Party debate, Paul continued to elaborate on why he blamed the United States for the attacks.
The booing didn't phase Paul.
At the end, he concluded, "Would you be annoyed? If you're not annoyed, then there's some problem."
Media mogul Donald Trump left many a heads scratching when he ended his would-be campaign, before he even began it.
"I maintain the strong conviction that if I were to run, I would be able to win the primary and ultimately, the general election," Trump said in a statement in May of the speculation that he might run on the Republican ticket. "I have spent the past several months unofficially campaigning and recognize that running for public office cannot be done half heartedly. Ultimately, however, business is my greatest passion and I am not ready to leave the private sector."
The confusing announcement left many wondering whether the reality show host staged the entire incident just to boost ratings for his TV show.
He had even set a date for his campaign announcement, May 25 in the atrium of Trump Tower in New York City.
The 2012 campaign season has been filled with "oops" moments and perhaps no one has had them more than the Texas governor who coined the term on the trail.
After first flubbing his response to which federal agencies he would cut as president, Perry misstated the number of Supreme Court justices.
"When you see his appointment of two, from my perspective, inarguably activist judges whether it was..." Perry said in the Des Moines Register editorial board meeting in early December.
He then pausing for six seconds, then continued, "Not Montemayor..."
"Sotomayor," a member of the editorial board interrupted.
"Sotomayor, Sotomayor," Perry said. "And Kagan are both activist judges."
Shortly after this flub, Perry referred to "eight unelected" judges when discussing who should decide whether prayer is allowed in schools.
But there are nine Supreme Court justices, not eight.
Newt Gingrich may be riding high in the polls as the year ends, but the former Speaker's campaign got off to a rocky start this summer when a slew of his senior staff resigned en masse.
Many of the 16 aides who left cited lack of organization on Gingrich's part and frustration with the direction of the campaign.
Just as the campaign season was beginning to pick up steam, Gingrich went to vacation in the Greek Isles with his wife, Callista.
Former Minnesota Gov. Tim Pawlenty dropped out of the Republican race in August after after a disappointing third place finish in the Iowa Straw Poll.
Pawlenty said he was disappointed his message didn't get traction with voters and he said the poll showed that "if we didn't do well in Ames, we weren't going to have the fuel to keep the car going down the road."
Pawlenty later endorsed Mitt Romney.