Hot Topics: Oprahmania, Diana Nyad, Steven Tyler, Ron Howard and Kirstie Alley

Howard Camping, the radio evangelist who recently prophesied the impending demise of the world, apparently got his signals crossed. Actually, it was Oprah Winfrey's daytime TV show that ended this week. But in fairness, the grand dame of the afternoon airwaves' finale to her 25-year run was a pretty big deal.

From Oprah's website, here's a slideshow depicting the veritable pantheon of celebrities -- Tom Hanks, Madonna, Beyonce, Tom Cruise and Katie Holmes, and even pint-size child opera singer Jackie Evancho of America's Got Talent fame -- who showed up to pay homage to the 57-year-old talk show host-turned-multimedia entrepreneur and inspirational figure. But wait, that was just the first half of the two-hour televised extravaganza that was so sprawling that it was held at United Center, the arena that is home to the NBA's Chicago Bulls. Part II featured a performance of "Amazing Grace" by Queen of Soul Aretha Franklin and an appearance by Maria Shriver, about whom you've undoubtedly been hearing a lot lately. My favorite moment, though, was this song-and-dance sendoff -- Peggy Lee's "Fever" performed by former daytime talk-show star Rosie O'Donnell, with Winfrey proteges Dr. Phil McGraw and Dr. Mehmet Oz doing a little soft-shoe in support.

It's as good a time as any to contemplate the 57-year-old Winfrey's remarkable achievements. She's the quintessential American success story, the child of a teenage single mother in hardscrabble rural Mississippi, who rose through hard work to become a multibillionaire and and taste-shaper in popular culture and commerce, so influential that Forbes.com recently proclaimed her No. 3 on its list of the world's most powerful women. Starting in the 1990s, she transformed the oft-tawdry, titillating genre of daytime TV into an inspirational platform that uplifted both her viewers' spirits and their intellects, and spurred them to take action to improve both their own lives and the communities around them. From CNN.com, here's a thought-provoking essay entitled "How Oprah Became a Messiah," by Yale University religious historian Kathyrn Lofton. PBS.org has this fascinating quantitative analysis of the so-called "Oprah Effect," from the 55 million books sold by authors who've been fortunate enough to be touted by her book club, to the $350 million that she has given to charity. Here also is a forward-looking article from the Hollywood Reporter, exploring whether Winfrey's transition to full-time stewardship of her fledgling, so-far-struggling OWN channel will transform it into a dominant force in cable TV.

Now for the rest of the week's boomer-centric news.

Will Diana Nyad make her Cuba-to-Florida swim this summer? As reported in this SecondAct piece last year, the 61-year-old open-water endurance swimmer dreams of completing the torturous 103-mile swim that she first attempted back in the late 1970s. Unfortunately, a stretch of awful weather prevented her from trying it in 2010. But The Washington Post's Sally Jenkins reports that Nyad is training hard with the aim of accomplishing her goal this summer. This time, Nyad's assembled a 25-member support team that includes a meteorologist and oceanographer, who'll use satellite imaging and other tools to select a three-day period in which the water temperature, wind patterns and currents are optimal. The big obstacle this time seems to be money; Nyad, who's been depleting her savings to finance her quest, still needs to raise about $300,000 to cover her expenses. (Oprah, are you reading this?)

Steven Tyler shows how it's done: In case you didn't catch this week's American Idol finale, here's a video clip of rock icon-turned-talent judge Steven Tyler's breathtaking rendition of his late 70s hit "Dream On." Wow, he can still hit those glass-shattering high notes at the end.

Middle-class boomers now plan on working to age 70: A new report released this week by the Bankers Life and Casualty Center for a Secure Retirement found that middle-income boomers are delaying retirement by an average of five years. Uncertainty about Social Security and Medicare, the steady decline of defined-benefits pension plans in favor of 401(k)s and continuing unease about the stock market are the key factors. One silver lining: This will give boomers who have retirement savings of less than $100,000 -- that is, 55 percent of them -- more time to amass them. Another possibly significant finding, though I'm not sure exactly what it means: Two-thirds of middle-income boomers aren't receiving any professional advice on their retirement planning.

Air-conditioned gypsies: I've been looking for an excuse to sneak a Pete Townsend lyric into this blog for a while, but with this story, it actually fits. SmartMoney reports that many boomers -- that is, at least the ones who can afford to retire -- are buying pricey tricked-out RVs that sound nearly as opulent as the Palace of Versailles. As reporter Catey Hill explains, "buyers have gotten used to stainless-steel appliances, flat-screen TVs and hardwood floors in their primary residence; now they want them in their mobile homes, too." The downside: The luxury leviathans typically get just eight miles to the gallon, which translates to spending $1,500 at the pump for a New York to LA drive.

Worried about developing Alzheimer's? Maybe you should have a glass of wine: ScienceDaily reports that a new study, published this month in the Journal of Alzheimer's Disease, suggests that alcohol consumption may help protect against the devastating neurological ailment. Spanish researchers found that light to moderate drinking seemed to reduce the incidence of Alzheimer's, particularly among female nonsmokers.

They'll have to find somebody else to star in the remake of Fat Actress: Okay, so Kirstie Alley didn't win season 12 of Dancing With The Stars, but the former Cheers star's startling physical transformation really overshadowed, ah, whoever it was who did. The Huffington Post reports that the 60-year-old actress's cha-cha costume had to be taken in an astonishing 38 inches in the two and a half months between the first episode and when she wore it again in the finale. According to her website, Alley whittled away 70 pounds during that time, with a combination of dancing and a new organic diet regimen that she's promoting.

Superstar movie director Ron Howard seeks inspiration from amateur digital photographs: Geoff Boucher of the Los Angeles Times reports that the auteur behind Apollo 13 and A Beautiful Mind increasingly is fascinated with digital photography and the internet, and ordinary folks' ability to create powerful images and communicate them to the world. To that end, Howard, 57, is launching a joint venture with camera maker Canon, in which he'll take eight unrelated images from a company-sponsored photography contest and weave them together to make a short film. Says the former child star of The Andy Griffith Show: "I think that is going to push me and all of us involved in this project outside of the box in a way that is fresh and exciting."

Who is greater: Bob Dylan or Paul Simon? To a lot of their boomer fans, it probably seems almost sacrilegious to ask; you might as well pick between Willie Mays and Hank Aaron, khaki vs. denim, single-malt vs. blended, or the The Godfather vs. The Godfather Part II. Nevertheless, the Forward's incomparably brave critic David Shasha gives it a try in this insightful essay.

And finally: The Wall Street Journal reports that Martha Stewart's eponymous company may be for sale. And according to an article in Slate.com, former CBS Evening News anchor Katie Couric is close to signing a deal with rival broadcast network ABC, which would include both launching a syndicated show and covering high-profile news stories.