In the midst of the Mad Cow disease hysteria, Oprah interviewed a former cattle rancher/vegetarian activist about the beef industry and told her viewers that the activist's allegations "stopped [her] cold from eating another hamburger." When beef prices fell to a 10-year low after the show aired, Texas cattle ranchers sued Oprah for defamation. A jury ultimately ruled in her favor.

No one who saw Tom Cruise's bizarre pronouncement of his love for new girlfriend Katie Holmes will ever forget it. Cruise couldn't contain his excitement, jumping up-and-down on Oprah's couch and grabbing her hands, exclaiming: "I'm in love! I'm in love!" While most viewers dismissed Cruise's conduct as a publicity stunt, the interview spawned amusing viral videos like the one below.

Oprah's weight has long been a hot topic, but never more so than after the episode in which she revealed her new physique by appearing on her show in size 10 jeans, pulling a wagon full of 67 pounds of fat to represent the weight she had lost. Oprah wasn't able to keep the pounds off and, more than 20 years later, people are still talking about her weight.

Less than a year after the Oprah Winfrey Leadership Academy for Girls opened in Johannesburg, the boarding school for gifted but impoverished girls was rocked by allegations of sexual and physical abuse made by 15 students against a dorm matron. Oprah, who founded the school with $40 million of her own money, called the incident "devastating." Watch her address the allegations in the video below.

With more than 90 million viewers worldwide, this sit-down interview with Michael Jackson at his Neverland Ranch was the highest-rated episode in the 23 years Oprah has been on the air. Jackson, who hadn't given a televised interview in more than 14 years, talked about his plastic surgery, his girlfriend at the time, and the disorder that stripped the pigmentation from his skin. See the one question he refused to answer below.

When an episode of Oprah about teen sexuality devolved into a graphic discussion about what it meant to get a "tossed salad," Howard Stern - long a target of the Federal Communications Commission - urged his listeners to file complaints with the agency. Stern argued that if a similar discussion about "oral anal sex" took place on his program, he'd be cited for indecency. In response, the FCC received more than 1,600 complaints about Oprah's show. Watch the offending clip below.

When Oprah selected Frey's A Million Little Pieces for her book club in 2005, the gritty memoir about Frey's battles with substance abuse became an instant best seller. But when The Smoking Gun published the results of a lengthy investigation that debunked many of Frey's stories, Oprah responded with a vengeance. With Frey and his publisher on her program, Oprah sternly lectured the embarrassed author, creating one of the most awkward moments in Oprah history.

When an employee at Hermes in Paris turned Oprah away late one day, a spokesperson at her production company referred to the incident as "Oprah's Crash moment," a reference to the film about racial tensions in Los Angeles. Was Oprah barred from Hermes because it had been "having problems with North Africans" or merely because it had just closed for the day? Either way, Oprah lambasted Hermes, and the store's president appeared on her show to publicly apologize.

It took 16 years, but Oprah's visit to The Late Show resulted in the end of her long-standing feud with David Letterman. Although the assumption was that their disagreement stemmed from Letterman's frequent jokes about Oprah during his nightly monologues, Oprah - on the show to promote the Broadway version of The Color Purple - told Letterman that she had no idea why they were feuding. Watch the first half of her appearance below.

In late 2002 and early 2003, in response to growing sentiment that military action in Iraq was inevitable, Oprah ran several episodes in which she analyzed the appropriateness of invading Iraq, as well as the potential ramifications of such an action. Oprah even broadcast a two-day special regarding world views in Iraq beginning the day after Secretary of State Colin Powell address the United Nations on the conflict. While anti-war advocates lauded Oprah, the Bush Administration was purportedly less than pleased.

This was perhaps the all-time happiest episode of Oprah. After her staff secretly handpicked each of the audience members because each one needed a car, Oprah surprised them all by giving each of the 276 in attendance a brand-new Pontiac G6 sedan. General Motors picked up the tab for the cars, which were worth nearly $30,000 each. And while the studio audience went crazy, reality set in later, as each member of the audience had to pay about $7,000 in taxes or lose their new car. Check out a cool remix of the giveaway below.

Oprah was criticized earlier this month for her interview with Mike Tyson, who talked about having wanted "to sock" his ex-wife, actress Robin Givens. While the audience laughed uncomfortably, Oprah didn't address the boxer's comments. Last week, Givens appeared on Oprah and told Oprah that she was hurt by her silence in the face of Tyson's comments. Oprah issued a lengthy apology to Givens and "every women in that situation for not being sharp enough." Watch the offending portion of Oprah's Tyson interview below.

Since the inception of her show, Oprah frequently has aired episodes providing health tips to her millions of viewers. While many of these tips are given by physicians like Dr. Phil McGraw and Dr. Mehmet Oz, some are offered by celebrities such as Suzanne Somers (promoting hormone therapy) and Jenny McCarthy (regarding autism). In a recent cover story, Newsweek took Oprah to task for McCarthy's unchallenged description of the link between austism and vaccinations, as well as several other Oprah episodes focusing on health issues.