This coming weekend, the Watermill Arts Center, founded by Robert Wilson to nurture young artists from around the world, will celebrate the grand opening of its new building with a lavish benefit on Saturday and public events on Sunday.This past Saturday, the Parrish Art Museum in Southampton hosted its annual Midsummer Party and unveiled plans for a new 80,000- square-foot facility, to be designed by the world-renowned architectural firm Herzog & de Meuron. East Hampton’s Guild Hall, which is celebrating its 75th anniversary this year, recently opened a new education center and is in the midst of a capital campaign to renovate the John Drew Theater.

For many years, the Hamptons have been both a haven for artists and a magnet for New York’s moneyed class. But people involved in the arts there said that the cultural calendar is now more and more crowded. “If you take a look at the East Hampton Star or Dan’s Papers, there’s 30 events going on any weekend,” the chairman of Guild Hall, Mickey Straus, said.

How much culture can the area sustain? “They say, ‘Why do you rob banks?’ ‘Because it’s where the money is,'” Mr. Straus said. “People are developing these projects because there’s an audience for it.”

Moët Hennessy Louis Vuitton has sponsored the summer benefit at the Watermill Arts Center for the last six years.”We sell out every year — it’s the party of the summer,” the executor director of Byrd Hoffman Foundation, which runs the center, Charles Fabius, said. Tickets are $1,000. With the new building opening,the party this coming Saturday night will be particularly festive, with a lengthy roster of starry attendees from almost every discipline, including Edward Albee, Mikhail Baryshnikov, Renée Fleming, Richard Meier, Chuck Close, and Sharon Stone. On Sunday evening there will be a redcarpet premier of a film about Mr. Wilson — “Absolute Wilson,” directed by Katharina Otto-Bernstein.

For artists, the proximity of patrons and museums is a plus. “For a resort to have that level of firepower” is unusual, said the painter Donald Sultan, who has a house in nearby Sag Harbor.

And for patrons, going to events in the Hamptons is an appealing way to carry on their social and philanthropic life from the city, but in a more relaxed atmosphere. “It’s great, because it’s much more integrated with our children — it’s not going to a lot of fundraisers at night where you leave the kids at home,” a composer and a supporter of both the Parrish and the Watermill Center, Lucia Hwong Gordon, said. At the Watermill benefit, for instance, “If we go on the early side, we take the kids, and then they go home and go to bed, and we stay,” Ms. Hwong Gordon said. “It’s great for them to experience it: to see the art and the performances and walk through the forest and see how they transform the trees.”

Mr. Wilson founded the Watermill Center in 1992, as a place for artists from different countries and working in different mediums to come during the summer and work in close contact with one another. In the late 1980s, Mr. Wilson saw the property in Watermill, which included an abandoned Western Union factory. He was drawn to the incongruity of an industrial building marooned in the bucolic Hamptons, Mr. Fabius said. Mr. Wilson purchased the property in 1989 and in 1991 donated it to the Byrd Hoffman Foundation, which he had started in the late 1960s.

“It’s like an idea factory,” Mr. Fabius said. “People work together who normally would be isolated, like an architect or a painter. The performers are more used to working in groups,but,for them, to work with an architect or designer is a new experience.”

Over several years, Mr. Wilson and his protégés, including the New York architect Frank Michielli, designed the plan for the new building, based on the blueprint of the U-shaped factory. The new building includes a dormitory, a dining room and kitchen, a doubleheight rehearsal/performance space, six artist’s studios, and a residence for either Mr. Wilson, when he is there, or an invited artist or scholar. Mr.Wilson’s eclectic art collection, which ranges from Pre-Columbian and Oceanic objects to 20th-century design, is displayed indoors and outdoors; currently,a collection of Indonesian tombstones is installed in the beechwood forest that covers much of the 6-acre property.

The final phase of construction, in the last two years, cost $4.3 million; total costs were around $12 million. The attacks of September 11, 2001, held things up, but the center in the end attracted the funds of many powerful foundations, corporations, and individuals, including the Brown Foundation, the Peter J. Sharp Foundation, Rolex, Armani, Donna Karan, and Beth Rudin DeWoody.

The summer benefit is a way to make tangible to the Center’s patrons what happens there. Donors are also encouraged to stop by any day during the summer to see what the artists are working on and have lunch, Mr. Fabius said.

Both the Parrish Art Museum and Guild Hall also are engaged in major construction and renovation projects, to be financed partly with funds raised from their deep-pocketed board members. The Parrish announced last summer that it had chosen Herzog & de Meuron, the firm that did the Tate Modern in London and the new de Young Museum in San Francisco, to design its new facility. A spokeswoman said the museum has not yet determined how much construction will cost.

Mr. Close, who has been involved with the Parrish Museum over the years and is a friend of its director, Trudy Kramer, said that that the new building will, for the first time, take advantage of the East End’s famous light. The most important thing about the Hamptons to him as a painter,Mr.Close said,is the way the light bounces off the water.

“It’s an absolutely amazing place to paint,” he said. “And one of the most exciting things about the new Parrish is that its design will use natural light.For the first time, it will be an opportunity to see work that was made out here — from the turn of the last century ’til right now — in the light under which it was painted.”

In June, Guild Hall opened its new Boots Lamb Education Center, built with a million-dollar gift from Marjorie Chester, in honor of Elizabeth (Boots) Lamb, who was also a longtime supporter of Guild Hall. The new building allows Guild Hall to offer much more educational programming, including studio art classes for children and adults and classes tied in with gallery exhibitions, including, this summer, shows of Andy Warhol and the painter Elizabeth Peyton.

The next project is the renovation of the John Drew Theater. There will be better seats and more room around each seat, as well as a complete technical and acoustical upgrading, said Guild Hall’s executive director, Ruth Applehof. “The whole theater will be restored,” Ms. Applehof said. “It has a gorgeous design, and we want to bring that back to life.” Guild Hall is currently raising the funds for the renovation through a “major gifts committee” of the board, of which one board member, Michael Lynne, is the chairman.

For now, the Watermill Center, the Parrish Art Museum, and Guild Hall all seem to attract enough local wealth and patronage to sustain their expansion. “In terms of constituencies” — with the Parrish in Southampton and Guild Hall in East Hampton —”it just comes down to who lives where,” Mr. Straus said.

The Watermill Center, at least for now, does not have a public function. Apart from donor visits, it is typically closed to the public, although Mr. Fabius said that anyone who is interested can call the Byrd Hoffman Foundation and arrange for a tour.This coming Sunday afternoon, in honor of the new building, the center will be open to the public from 2 to 6 p.m. There will be guided tours of the building and the grounds, musical performances and art installations, and interactive workshops for children and adults. Admission is free.

The center also wants to collaborate with both the Parrish and Guild Hall.Mr Fabius would like the center’s resident artists to be able to show their work at the Parrish. And this summer, Mr. Wilson will be putting on performances of his production, “Persephone,” in the John DrewTheater on August 12 and 13.

“We are totally complementary”with the other institutions in the area, Mr. Fabius said.”We’re a laboratory.We’re a think tank.”

Of course, only in the Hamptons could a think tank throw the party of the summer.