Maybe A.J. Jacobs and his cousin actor Daniel Radcliffe (aka Harry Potter) will have a butterbeer at the reunion. Maybe A.J. Jacobs and his cousin actor Daniel Radcliffe (aka Harry Potter) will have a butterbeer at the reunion. Maybe A.J. Jacobs and his cousin Daniel Radcliffe (aka Harry Potter) will have a butterbeer at the reunion. (Photo: Courtesy Global Family Reunion)

Grab your suitcase: You're invited to the must-attend party of summer

How a bestselling author was inspired to throw the world's largest family reunion.

On Monday, June 8, 2013, at 12:21 PM, a dairy farmer in Israel sent an email to a bestselling author in the U.S. In it, the dairy farmer described the long branches of his family tree, winding back 20 generations, all the way to a German man named Meir Katzenellenbogen born in 1482. The dairy farmer ended the email to the bestselling author with this simple line: "You are a 10th cousin of my wife who, in my opinion, is a fine lady."

Thus began a quixotic quest that would lead author A.J. Jacobs down a rabbit hole from which he will finally emerge this weekend. Exactly two years after that initial email was sent, which led Jacobs on a hunt for more long-lost relatives, he's hoping to pull off the unthinkable: Hosting the world's biggest family reunion ever.

Jacobs is no stranger to stunts of epic proportions. For his book "The Know-It All: One Man's Humble Quest to Become the Smartest Person in the World," he read the entire Encyclopedia Britannica cover to cover. All 33,000 pages and 44 million words, all the way from Aak to Zywiec. For his most recent New York Times bestseller, "Drop Dead Healthy: One Man's Quest for Bodily Perfection," his goal was nothing short of becoming the healthiest man on the planet.

So what's a little family reunion?

Dr. Oz is my A.J. Jacob's great aunt's husband's fourth great niece's husband's second great granddaughter's husband's second cousin's husband.Dr. Oz (left) is A.J. Jacobs' (right) great aunt's husband's fourth great niece's husband's second great granddaughter's husband's second cousin's husband. (Photo: Courtesy Global Family Reunion)

The event this weekend at the New York Hall of Science, however, is anything but little. Dubbed the Global Family Reunion, it will include three stages, more than 50 TED Talk-style speakers along with more traditional family reunion activities like potato sack races and scavenger hunts. Legendary rock group Sister Sledge will be performing, appropriately, "We Are Family." The Guinness Book of World Records will be on hand to snap the world's largest family photo.

And to think this all started with a dairy farmer in Israel named Jules Feldman. His email to Jacobs, on a whim, has led to this. "When I Googled him and saw what he was up to, it struck me that if anybody could do something with this information, it would be A.J. I was incredibly surprised when he took up my challenge," Feldman told From the Grapevine on a late-night call from his farm in northern Israel. "A.J. has got a good imagination and he knows how to take things to the extreme."

Christina Hendricks of "Mad Men" fame is likely your cousin.Christina Hendricks of "Mad Men" fame is a cousin of A.J. Jacobs, and likely your cousin as well. (Photo: Courtesy Global Family Reunion)

Impressing Feldman, a self-proclaimed genealogy buff, is no small feat. The South African native claims relation to all manner of people. He's found relatives in Canada and Alaska. He even discovered that he's related to a 16th-century man who was king of Poland – for a day.

With the growth of genealogy websites like Ancestry.com and TV shows like "Who Do You Think You Are?" and "Finding Your Roots," discovering who you're related to has become de rigueur. Jacobs has been using many tools on his search including MyHeritage. The Israel-based website, which helps people around the world fill in the branches on their own family tree, is also helping Jacobs organize the reunion.

By using the service, Jacobs has discovered he's related to just about everybody. Harry Potter's Daniel Radcliffe is a distant cousin. So is former President George H.W. Bush. It turns out Judge Judy is his eighth cousin four times removed. Which means you – yes you, dear reader – are also invited (tickets are still available) since it's more than likely you are somehow related to both the dairy farmer and bestselling author. "I want you guys there," Jacobs says. "Figure out how you're on the family tree. Cousin to cousin, I can't wait to see you."

And if you can't make it to New York City, don't worry. Jacobs has organized 30 satellite parties across the globe – from Salt Lake City to Bulgaria and from Texas to New Zealand. The event will be live streamed on the Internet for all to see. The reunion will also double as a charity fundraiser to raise money for Alzheimer's research.

A.J. Jacobs discovered he was related to actress Olivia Wilde.A.J. Jacobs discovered he was related to actress Olivia Wilde. (Photo: Courtesy Global Family Reunion)

"One of the things that's marvelous about family trees is that you're the center of your world," Feldman says. "Nobody has the exact same family as you have. You're drawing your own concentric circles around you which meet up with those of others, but are never exactly the same."

As for Jacobs, a 47-year-old father of three, the hunt for distant cousins has given him a new appreciation for family. The resulting reunion will be fodder for his next book, tentatively titled "It's All Relative." The real writing will begin Monday morning, once the final relative has left town and Jacobs can get back to work. He says the book will likely come out next fall.

Jacobs, a native New Yorker, knows who he has to thank for all this. "I'm incredibly grateful to Jules for kicking this adventure off with his mysterious email," Jacobs told From The Grapevine. "I'm honored to call him a cousin, even if it's a distant one."

As for Feldman, the 66-year-old father of five says his interest in genealogy research goes beyond mere hobby. It's his gift to future generations. Although his kids don't think it's that grand. When asked what their father does, they jokingly reply: "Daddy milks cows and finds lost relatives."

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Grab your suitcase: You're invited to the must-attend party of summer
How a bestselling author was inspired to throw the world's largest family reunion.