Everyone knows that Carl Reiner is a comedy legend, and his recent books have been as popular as his TV shows. In fact, his last, "Too Busy to Die," was part of the inspiration for one of HBO's most successful documentaries. The entertaining and inspirational "If You're Not in the Obit, Eat Breakfast" introduces viewers to active, interesting, talented people who are living life to the fullest even though they are over 90 years old.

A lot of the people we meet during this 90-minute documentary are Hollywood celebrities, and many are Reiner's friends. After watching him spend time with entertainment legends like Mel Brooks, Dick Van Dyke, Norman Lear, Kirk Douglas and Betty White, you almost can't help but wonder whether 90 is the new 65.

Back in 2010, George Shapiro, Reiner's nephew and the film's producer, started keeping a paper file of energetic and inspiring older people titled "Vitality After 90," and, with his uncle's blessing, he self-financed the documentary. The very good news is that unlike so many creative projects that deal with the elderly and aging issues, this film is undeniably upbeat. Norman Lear, who finds it irritating that younger people are astonished he can still touch his toes, has no patience with people who apply negative stereotypes to the elderly. In his opinion, it's not realistic to continually view older people "as infirm, as whiny, and as incapacitated and foolish."

If you missed the documentary when it first aired on June 5, you can find it on HBO on demand. Or, if you don't want your own subscription, find a friend who gets the channels, so you won't miss this dose of joie de vivre. Reiner asks all kinds of questions: Are vibrant elders simply lucky, or did they win the gene lottery? Are good nutrition, regular exercise and modern medicine the answer?

The individuals we meet seem to reflect aspects of all of those "elderly helpers," but the real answer seems to be as much emotional as it is physical. It's encouraging viewers to meet men and women who seem to have tapped into two very important aspects of aging well: maintaining close friendships and participating in activities that bring you joy.

We meet an amazing 100-year-old woman named Ida Keeling, who has become a legendary award-winning track star. Last year, she set a record for her age group in the 100-meter dash. The filmmakers share her story and how Keeling started running at the age of 67 when her daughter, a track coach, urged her to exercise as a way to overcome her sorrow over the drug-related deaths of her two sons.

We also meet a pianist named Irving Fields, 99-year-old yoga instructor Tao Porchum-Lynch and former Broadway actress 102-year-old Patricia Morison who appeared with Yul Brynner in "The King and I." Jerry Seinfeld, whose late mother was a much-valued part of Reiner's circle, shares his observations about people who are over 90 but still brimming with life. He's so inspired by the elders he's met that he has reportedly already booked Caesar's Palace in Las Vegas to host and perform at his 100th birthday comedy show in 2054!

Marilyn Murray Willison has had a varied career as a six-time nonfiction author, columnist, motivational speaker and journalist in both the U.K. and the U.S. She is the author of The Self-Empowered Woman blog and the award-winning memoir "One Woman, Four Decades, Eight Wishes." She can be reached at www.marilynwillison.com. To find out more about Marilyn and read her past columns, please visit the Creators Syndicate webpage at www.creators.com.