The extended Romney family at their vacation home on the shore of Lake Winnipesaukee in Wolfeboro, N.H. in July 2007. (Jon Moe/ASSOCIATED PRESS)

This weekend, Mitt Romney is starting his annual summer vacation on his lakefront compound here — a week of fun and family, though not entirely carefree.

The Romneys, 30 in all these days, spend their time away from the stresses of everyday life — like, say, wrapping up the Republican nomination for president — by following a highly orchestrated, highly competitive regimen of sports and games known as the “Romney Olympics.”

The Romney Olympics have long included a mini-triathlon of biking, swimming and running that pits Mitt and his five sons and their wives against one another. But after Mitt once nearly finished last, behind a daughter-in-law who had given birth to her second child a couple of months earlier, the ultra-competitive and self-described unathletic patriarch expanded the games to give himself a better shot.

Now they also compete to see who can hang onto a pole the longest, who can throw a football the farthest and who can hammer the most nails into a board in two minutes — not exactly the kind of events they’ll be giving out gold medals for in London this month.

By day, the Romneys kayak and water ski — one sport at which Mitt excels — play tennis and basketball, stage a “home-run derby” and horse around on a slip-and-slide. Most of the grandchildren (there are now 18) put on a talent show on a stage that Papa, as they call Mitt, constructed in the backyard. And he helps them roast s’mores over a campfire and leads them on treasure hunts. He grills chicken and salmon and teaches the kids how to drive his lawn tractor.

At night, the adults gather for family meetings, with each evening focused on a frank and full discussion of a different son’s career moves and parenting worries.

Each member of the family picks a daily chore from a “chore wheel,” so as to share cleaning tasks evenly. And before anyone departs, everyone poses on the lawn for a portrait for that year’s Romney family Christmas card. The grandchildren coordinate outfits; last summer, the girls wore matching orange and yellow polka-dotted dresses and the boys, blue checkered shirts.

How Romney vacations at his $8 million estate on Lake Winnipesaukee — with his time structured around competitive sports, household chores and group activities — offers a rare window into the presumptive Republican presidential nominee’s rhythms and proclivities.

Even as the close-knit clan embraces the childhood pastimes of a bygone era, summers here serve to enforce the bond of the primacy of this family. Trips to Wolfeboro are controlled and mandatory. There is no opting out.

One summer when Romney’s eldest son, Tagg, now 42, was working for the Los Angeles Dodgers, he told his father he wouldn’t make it to Wolfeboro. Baseball, after all, is a summer sport, and he didn’t think he could take a week off in the middle of the season.

“My dad said, ‘No, you will make it,’ ” Tagg recalled in an interview. So he showed up, noting, “I had to beg forgiveness from my bosses at the Dodgers.”

Other political families have had their athletic pursuits — the Kennedys at Hyannis Port, Mass., and the Bushes at Kennebunkport, Maine — but it’s not clear if they were as highly organized as the Romney Olympics.

A couple of little things will be different this summer at Camp Romney. For one, Papa is the presumptive nominee, and talk of vice presidential possibilities and other pressing concerns could filter into the family conversation. Also joining the fun will be an entourage of Secret Service agents, standing guard on the secluded property, with a hungry press corps lurking nearby — perhaps even watching the house from boats offshore.

Tagg Romney said the family is “focused on getting him elected, and we’re not focused on anything beyond that. We will not talk about if he wins, what does it mean for the family. We think it’s bad form to talk about that stuff if you don’t know whether you’ll get there or not.”

Romney’s 13-acre estate features a six-bedroom house, a horse stable with guest apartments above it, a $630,000 boat house, tennis and volleyball courts and a shoreline stretching 768 feet, more than double the length of a football field, according to public property records.

Romney and his wife, Ann, purchased the home in 1997 for $2.5 million and later bought adjoining land. This year, records show, the estate was assessed at $8 million.

It’s a property big enough to fit everyone, although the five sons have been e-mailing to negotiate sleeping arrangements. Some grandchildren will be relegated to couches and air mattresses.

Mitt Romney first vacationed in Wolfeboro with his father, George, at the estate of family friend J.W. Marriott, the hotel magnate. Over the years, many other well-to-do Mormon families have made the town their summer home, too, and on Sundays the Romneys join them at church on North Main Street.

The Romneys like to gather here around the Fourth of July, when Wolfeboro has what one resident called a “bang-up parade,” complete with a “lawn chair brigade” that performs routines tossing folding chairs in the air. Mitt Romney and his family plan to march in Wednesday’s parade, likely his only campaign event during his first full week of vacation since last summer.

“It’s the week that most of us look forward to more than any other week of the year,” Tagg Romney said. He added that his father “loves spending time with his grandkids. He reads them books, he takes them on boat rides, he takes them on bike rides and family walks.”

In Wolfeboro, dubbed “the oldest summer resort in America,” Romney’s neighbors said he and his family mostly keep to themselves. John Corf, who lives in a small home on an adjoining property, called Romney “a fine neighbor,” but added, “I’m not involved socially with them.” Corf said he has not seen Romney since last summer, when he bought Romney’s book, “No Apology,” and asked for his autograph. Romney walked over to Corf’s house to sign it.

Many residents here said they support Romney’s campaign but worry about the impact a win could have on this quaint hamlet of about 6,000. Again and again, shop owners along Main Street said they feared Wolfeboro turning into Kennebunkport, the seashore town where traffic and development boomed during George H. W. Bush’s presidency.

Many residents here are protective of Romney. Joe “Bucky” Melanson, who owns a jewelry store that the Romneys frequent, declined to detail what the candidate has purchased there. “That’s kind of personal stuff,” said Melanson, a Romney family friend.

The candidate who so often seems uptight appears to let loose here, as he zips across Lake Winnipesaukee on his speedboat filled with his young grandkids and pops into town for ice cream at Bailey’s Bubble (he’s a sucker for any flavor with peanut butter) or nails and plywood at Bradley’s Hardware.

“He walks in here in shorts and vacation clothes, with his grandchildren like little ducks following Papa Duck,” said Christin Kaiser, who has rung him up at Bradley’s.

Romney has been spotted at the grocery store, shopping with a list in one hand. And when he visits Main Street, he sometimes arrives by boat. Asked to describe the family, local retailer David Hemenway said: “All-American apple pie.”

Last winter in Iowa, Romney campaigned at a diner with his youngest son, Craig, who shared an anecdote from the Romney Olympics as an example of his father’s competitiveness.

Although Craig’s wife, Mary, had just given birth, she competed anyway in the triathlon.

“All the boys had finished at that point, and it was down to my wife and my dad,” Craig said.

“I tripped her!” Mitt quipped, joking.

“In the home stretch,” Craig recalled, “she had a slight lead on him and . . . he was going to win that race or he was going to die trying. And you see this fight to the finish. He went for this, he gave it everything he had, he gave it a good kick and he beat her in the end.”

Craig said his dad was so fatigued that “he passed out in the lawn chair, and we didn’t see him the rest of the day.”

“You know,” Mitt added, “there’s more to that. I changed the nature of the triathlon after that. I didn’t like this idea that these were only swimming, biking and running.”

Now, he said, “we have log-sawing, nail-hammering. We added some things I excel at so I don’t come in last every year.”