It's early August, the time of year when most NBA general managers can typically sneak in a little downtime, and yet Danny Ainge's phone won't stop buzzing.

The Boston Celtics president of basketball operations has flown to Provo, Utah, to support his son, Tanner, at a fundraiser toward a campaign for a seat in Utah's third congressional district (an election he'd lose in mid-August).

In what has already been one of the most dizzying offseasons of Ainge's NBA career, he finds himself in the early stages of negotiating a deal that will turn the NBA world on its head for nearly a month: a blockbuster trade centered on All-Star guards Kyrie Irving and Isaiah Thomas.

But, at this moment, Ainge needs a respite from trade talks. So he apologizes to a caller and hands his cellphone to his wife, Michelle.

"I need to call you back."

Then, dressed in black shorts, a black T-shirt with the words "highlight real" on the front, and a white visor, Ainge gingerly climbs the metal steps leading to a dunk tank seat he will occupy for the next hour.

Ainge peers through the wire cage in front of him and, amid the bounce houses nearby, sees a line of people who have gleefully paid $25 for the chance to send him swimming in a tub of cool water.

Ainge is typically a rock star here in the shadow of Brigham Young University, where his full-court drive to beat Notre Dame in the 1981 NCAA tournament remains one of the region's most celebrated sports moments. On this day, there's a handful of angry Utah Jazz fans who simply want a little revenge after Ainge's Celtics lured away Gordon Hayward in free agency earlier in the summer.

Soon enough, Ainge is soaked as softballs whiz at the red target to his left and he gamely high-fives those who trigger the release on his seat with their accurate tosses. Afterward, Ainge conducts a handful of interviews with local television stations while clinging to his grandchildren.

When the event finally winds down, it's back to the phone for Ainge. It has been a familiar sight this offseason.

All eyes were on Danny Ainge this summer, waiting on which move the Celtics president of basketball operations would pull off next. AP Photo/Elise Amendola

"It was a really busy summer," Ainge said recently while reflecting on Boston's blizzard of activity. "My golf handicap should be a lot better than it is right now."

Beyond the jaw-dropper trade for Irving, the Celtics dealt away the No. 1 overall pick in the 2017 draft and sent out their longest-tenured player, Avery Bradley, in order to clear cap space to ink Hayward. Boston also signed 12 players this summer, if you include rookie deals and a ceremonial signing of Celtics legend Paul Pierce so he could retire as a member of the team that drafted him.

It was an unprecedented roster overhaul, as no team to finish atop its conference in the regular season has ever brought back four players or fewer. The only players remaining from a team that won an East-best 53 games last season: Al Horford, Marcus Smart, Jaylen Brown and Terry Rozier.

Ainge shakes his head and smiles while thinking about all the activity, including all the moves the team didn't make (like, say, that planned pursuit of Paul George before Indiana surprisingly dealt him to Oklahoma City just before free agency opened).

"Sometimes it's busy and you don't get a lot done, and sometimes it's busy and there are wholesale changes," said Ainge, hinting that Boston's summer featured healthy scoops of both. "I'm really excited for this season but, yeah, it was a pretty busy summer."

"Busy" doesn't begin to describe it.

During the 72 hours after Hayward signed, Celtics assistant general manager Mike Zarren spent much of his time wandering the halls at the University of Utah's Huntsman Center, where the Celtics -- along with the Jazz, Philadelphia 76ers and San Antonio Spurs -- were playing in summer league.

Cellphone service was fleeting at best, but Zarren kept at it -- so much so that he carried a battery pack in his front pocket and was essentially tethered to it, trying to keep his phone powered on.

"It was one of those things where you had to kinda sit there and wait. It was kind of like a horror movie. 'Don't go behind that door!' You hear that music and it's like, 'OK, what's going to happen next?'"

While the Celtics had landed maybe the top available free agent of the offseason -- at least among players who weren't slam dunks to return to their teams -- they did not immediately have the cap space necessary to sign Hayward to his four-year, $128 million max contract. The league's other 29 teams started phoning Zarren, looking to see if they could fetch a consolation prize, knowing Boston had to make a tough decision.

Teams phoned inquiring about Bradley, Jae Crowder, Smart and much of Boston's younger talent. The Celtics didn't want to rush into a decision and tried to hear out all proposals. The calls were relentless.

Zarren admits now that those three days brought the busiest stretch of calls he has ever had with the Celtics.

As midnight approached in Utah on July 6, Celtics brass were combing through their trade offers and believed they had honed in on the move that made the most sense for the team. According to league sources, Boston was maybe minutes away from picking one of those deals when the Detroit Pistons unexpectedly called, rekindling discussions the two sides had engaged in earlier in the week.

The proposed swap -- Bradley and a second-round pick for Marcus Morris -- was even better than the deals Boston originally had on the table, and the two sides moved quickly to finalize an agreement.

The revamped Celtics have a new Big Three in Gordon Hayward, Al Horford and Kyrie Irving. AP Photo/Steven Senne

But even that plan hit a small snag. Both the Celtics and Pistons, out of respect to the players involved, wanted to alert them before news got out. Bradley was Boston's longest-tenured player and its last link to the most recent Big Three era. The team didn't want to move him but also recognized it likely couldn't offer him the big payday he'll likely earn as a free agent next summer.

The Celtics decided to call Bradley first thing the next morning, and the Pistons were going to do the same with Morris. But Bradley didn't pick up his phone and when the team finally tracked down his wife, Ashley, the Celtics found out Bradley had caught an early flight from Austin, Texas, to Seattle to attend a wedding. It would be impossible to alert Bradley before news of the deal leaked, as Detroit had already successfully informed Morris.

Bradley told Bleacher Report over the summer that he turned on his phone late in his flight and, connecting to the on-board Wi-Fi, was so inundated with messages that he knew immediately he had been dealt. Instead of scrolling through his messages, he opened a browser window and Googled his name. The first result told Bradley he was headed to Detroit.

Celtics players like to tease Horford about his social media indifference. "Grandpa Al," the oldest player on Boston's roster at age 31, checks his Instagram feed daily but isn't glued to his phone like most of his younger teammates.

It's late August and Horford has taken his wife, Amelia, and their two young children, Ean and Alia, to SunTrust Park to catch an Atlanta Braves baseball game.

"I'm walking through the parking lot and people are just like, 'Did you hear? Did you hear?'" Horford said. "I'm with my family and I'm not much of a phone guy; I had my phone put away. But everyone is telling me, 'You guys traded for Kyrie!' I was on my way to watch the game and people told me before I could even get a chance to look at the phone."

Horford admits that, initially, he wasn't sure he even believed what he was hearing.

"I was kinda like, 'Huh? What's up with that?'" Horford said. "Then I checked my phone and before I could even [check Twitter], Coach [Brad Stevens] had texted me and was like, 'Call me, we need to talk.'

"He never texts me, so I was like, 'OK, something is up.' I'll never forget that moment."

"It was a really busy summer. My golf handicap should be a lot better than it is right now."

Across the country in Denver, Smart was on his own social media summer hiatus. In the process of dropping 20 pounds, Smart had just completed a workout with NBA legend Chauncey Billups when his agent texted to say that Smart could be part of Boston's impending trade with Cleveland.

Smart didn't think much of the text, but then he saw ESPN's report that the Celtics and Cavaliers were finalizing a deal. Smart opened his Twitter feed and peered with one eye shut, in hopes he wouldn't see his name.

"It was one of those things where you had to kinda sit there and wait," Smart said. "It was kind of like a horror movie. 'Don't go behind that door!' You hear that music and it's like, 'OK, what's going to happen next?'"

The 23-year-old Smart, the No. 6 pick in the 2014 draft, marvels at now being the longest-tenured Celtic. It feels like an accomplishment to have simply survived Boston's summer overhaul.

Even beyond the roster makeover, the Celtics made sweeping changes to their medical and training staff. Longtime trainer Ed Lacerte and strength coach Bryan Doo were let go and the team hired Art Horne to work alongside Johann Bilsborough, the director of sports science.

As third-year guard Rozier bluntly put it last month: "To remain on the Celtics after a tornado happened, it's crazy."

Each year, the Celtics hang action photos of players above their lockers inside TD Garden. At the start of each new season, there are usually a few blank spots to fill in for rookies and offseason signees. This year, the team printed placards with a generic Celtics logo in order to fill the whopping 11 vacancies in the room.

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It's jarring, even for newcomers, how different this roster looks. Hayward has admitted how instrumental Thomas was in recruiting him to Boston in July, and Hayward looked forward to playing alongside him. The Celtics practically underwent a second makeover between the time Hayward agreed on July 4 and the time Irving was officially traded just before Labor Day.

"It's definitely tough for everyone around here, and I felt that," said Aron Baynes, who signed as a free agent in July. "But that's the business side of things, unfortunately. That's the league. It comes down to the business side of things a lot of the time. You gotta try to do what you can. It's one of those things where you make the most of what you got, and I think we got a great team here. I'm really excited to be a part of it."

Make no mistake, Hayward is just as excited to play alongside Irving. The two gushed about each other during their dual introduction in early September. That dual news conference happened, in part, because all of Boston's summer activity never afforded the team a chance to formally introduce Hayward before that.

During that conference, Hayward ran down all the different players Boston had acquired this season and expressed excitement. Irving, smiling next to him, leaned in with a proclamation.

"It's about to get crazy, G," Irving said.

Sorry, Kyrie, but it seems impossible that anything could be as crazy as this past summer. But Ainge won't be opposed if his players find a way to make the season as interesting as the construction of this new-look roster.