Dania Kaseeva performs during Quick Change.

David Maas and his wife, Dania Kaseeva, are the masterminds behind Quick Change, a speedy costume-switching act that leaves Oprah asking, "How did you do that?" "I could tell you, but then we'd have to make you disappear," David jokes.

During the act, they change costumes several times—and even switch Dania's hair color—behind fluttering, brightly colored cloths and falling confetti. Dania says men always tell her, "I wish my wife changed like you."

Dania got her start in show business in the Moscow Circus in Russia, and David's family has an entertainment background as well. The pair has been doing their quick-change act for 10 years, performing for such illustrious audiences as the Queen of England. To keep their patented quick-costume-changing techniques top secret, David says they don't let the costumes out of their sight! "We worked on it a long time," he says.
Spanx creator Sara Blakely

In 2000, Oprah discovered a miracle product and has been raving about it ever since—Spanx pantyhose. Oprah says the fabulous footless hose that "suck it all in" changed her life.

Spanx started as a simple idea when 27-year-old Sara Blakely was looking for a simple hose solution. Sara wanted to maintain the slimming effect of pantyhose—without covering her feet. By cutting the foot portion off of her favorite stockings, she got the best of both worlds! "They made me look a size smaller, smoothed everything out, got rid of the panty line, and I thought, 'This should exist for women!'" Sara says.

Sara says Oprah gave her the final inspiration she needed to move ahead with her idea. "I remember verbally saying, 'I'm asking for a sign.' I flipped on the end of Oprah, and that day, Oprah told the world that she had been cutting the feet off her pantyhose for years," Sara says.

At that moment, Sara cleaned out her $5,000 savings account and went for it. "I went to craft stores and found little bands and things that I thought could maybe go on the end of it," Sara says. "I researched yarns. The hosiery mill helped me—there are thousands of yarns to choose from—and we went through hundreds of prototypes before we came up with the original Spanx."

Take a look at how Spanx are made! Watch
Spanx creator Sara Blakely gives Oprah a surprise.

In just six years, Sara says Spanx has made more than $100 million in retail sales. "It's amazing. I mean, all the men that I was cold-calling [said], 'This isn't a good idea. I don't get it,' and [the business] just has taken off. I believed in it. You were such a big part of it," Sara tells Oprah. "The journey has been amazing, and I feel like you've been present almost the whole journey. I'm thrilled to meet you."

Sara recently went to South Africa and launched her own foundation. "I have been making the world a better place one butt at a time, but it is my dream to make the world a better place one woman at a time." Sara hand delivered 278 scholarships to send women in South Africa to college.

Sara's generosity doesn't end there—she has a big surprise for Oprah! "To me, the greatest part of success is what you're able to give back, and you're a great teacher of that," Sara tells Oprah. Sara announces that she will donate $1 million to the Oprah Winfrey Leadership Academy for Girls in South Africa!

"On behalf of all of our girls, all of our new daughters, thank you very much," Oprah says.
Cirque du Soleil's 'Mystère' performers Marco and Paolo Lorador

Marco and Paolo Lorador, performers in the Cirque du Soleil show Mystère, wow audiences night after night with their physical feats of strength and balance.

The brothers are third-generation performers from Portugal who have been in the business for 30 years. "My father was in the circus, my grandfather, and before we knew it, we were born into it," Marco says.

In graceful, controlled movements, Marco does a handstand on his brother's outstretched hands, then maneuvers into a one-handed handstand on one of Paolo's hands.

Marco and Paolo keep their muscles toned by working out and performing 10 shows a week at Treasure Island Hotel and Resort in Las Vegas. "It's just beautiful to watch," Oprah says.
Merl Reagle and Will Shortz are the brains behind 'The New York Times' crossword puzzles.

It's the national pastime that leaves more than 50 million people scratching their heads every week—crossword puzzles!

From baseball greats to heads of state, anyone can be a "puzzle head," including Daily Show host Jon Stewart and former President Bill Clinton. "I find it very relaxing," President Clinton says. "Sometimes you have to go at a problem the way I go at a complicated crossword puzzle. You start with what you know the answer to and you just build on it."

More challenging than the brainteasers themselves is how they're made. Merl Reagle has been designing puzzles by hand since he was six years old. He begins each puzzle with one word, and then fills in other words that generally correspond to a theme. Still, Merl always follows the rules: Only one-sixth of the diagram can be black squares, and the arrangement has to look the same whether you're looking at it right side up or upside down.

After finishing a puzzle, Merl sends it to The New York Times crossword editor Will Shortz, who sifts through about 70 puzzles a week. Will decides which puzzle will run on which day. If it's a Monday puzzle, the clues will be easy. The clues are always the most difficult on Fridays and Saturdays, Will says.

So what makes the perfect puzzle? "The perfect puzzle is one that stretches you to the limit, the one that you look at and think, 'I can't do this,' but then you do, and that's what gives you the great feeling of satisfaction," Will says.
Merl Reagle, Will Shortz and Oprah fill out an 'Oprah' crossword puzzle.

As it turns out, Oprah has a very popular name for crossword puzzlers because it starts with a vowel. "Just in the last 10 years, I think the Times crossword has used your name about 30 times," Will says. "My favorite clue that I've ever used for your name in The New York Times crossword is 'show of compassion.'"

Merl and Will even designed a special scrambler just for Oprah! Built in the shape of an 'O,' most of the clues are about Oprah and all 21 years of her show.

Some of the clues—like "Sophie's mom"—are easy; but as the puzzle goes on, they get more difficult. For example, who is Oprah's most frequent celebrity guest? You get five letters... And what are the two words (in three letters) that Oprah hasn't said?

Take the Oprah crossword challenge for yourself! PDF

"Oh, this is fun!" Oprah says.
Oprah parks the new Lexus without lifting a finger.

During her cross-country adventure with Gayle, Oprah revealed that she suffers from "interstate anxiety," "unpaved road anxiety" and "merging anxiety." Oprah also admitted a few other things she doesn't really like—night driving and driving over bridges.

Now, Oprah confesses to another driving roadblock. "So I will admit that I am not the best parallel parker, and when I heard about this new technology for your car, my producers said that I needed to see it," Oprah says.

With the help of Lexus Vice President of Sales Jim Colon, Oprah tries out the new Lexus that parallel parks itself. Once she's moved the car into a prime parking position, she puts it in reverse, which activates a rear camera to scope out the amount of space she has to park.

After confirming her position on a screen inside the car, Oprah hits a button and the car starts to move on its own. In a matter of seconds, the car is in the spot and Oprah hasn't lifted a finger! She puts the car in forward drive to straighten it out...and voila! "That is excellent!" Oprah says.
Jack Trimarco conducts a polygraph test.

According to a University of Southern California study, the average person is lied to every five minutes—about 200 lies a day!

Jack Trimarco, a former FBI investigator and world-renowned polygraph expert, detects lies for a living. Hundreds have tried to lie to him—and failed.

In order to conduct a polygraph test, Jack says there needs to be privacy, and the person has to be healthy and well-rested. "It's imperative that the examinee be aware of every question that's going to be asked on the test," he says. "No tricks. No surprise questions."

Nerves don't effect the results, he says. "Everybody's nervous that takes a polygraph test, whether you did it or you didn't do it," Jack says.

The test measures your respiratory function, sweat gland activity and cardio function through a blood pressure cuff and sensors. When you tell a lie, Jack says, a signal is sent to the rest of the body and produces a physical reaction that can't be hidden.

During the test, Jack asks only yes or no questions and monitors a scroll of paper that has four pens recording your body's physical reactions. Afterward, Jack is on the lookout for extreme peaks and valleys—the telltale signs of deception.igns of deception.