NEW ORLEANS -- IN Hollywood, causes tend to divide into the popular and the deeply personal. You usually can recognize the difference because the former come from the pages of next month's glossy magazines and the latter right from the heart.

For all the time he spends on the tabloids' covers, for example, Brad Pitt actually is pretty much a homebody, and his activism grows out of the years he's spent exploring and understanding the role domestic architecture plays in individual lives. It's a deeply personal journey that has led to a public conclusion: that an adequate and secure hearth and home are central to our well-being.

Over the years, Pitt has bought old California Craftsman houses and restored them, gathering every bit of literature he could find on the Arts and Crafts movement and its most famous local architects, Charles and Henry Greene. The actor became so interested in their iconic homes that he teamed up with scholar and restoration expert Randell L. Makinson to produce the most extensive book to date on the restoration of Greene & Greene's Blacker House, which had been stripped and abandoned. (Pitt provided black and white photos as a visual essay on the Pasadena home's rebirth.)

Pitt has spent time with Frank Gehry at his studio, tinkering with diagrams and models. And last winter, for his birthday, girlfriend Angelina Jolie gave him a special gift: a private tour of Fallingwater, Frank Lloyd Wright's architectural masterpiece that spans Bear Run, a creek that flows through woods about 50 miles southeast of Pittsburgh.

So it's only fitting that Pitt's deep regard for the built environment and his concern for housing as a social cause have come together in his most ambitious project to date -- "Make It Right" which aspires to nothing less than the reconstruction of New Orleans' storm-ravaged Lower 9th Ward.

Pitt, along with residents of the area, Democratic fundraiser and movie producer Steve Bing, and a team of world-renowned architects launched a national fundraising campaign this week to help the city recover from the devastation caused by Hurricane Katrina. Pitt and Bing have already pledged to kick in $5 million each toward project development and construction. (Another difference between popular and heartfelt causes is their shelf life. Ruined New Orleans may not be an issue in the current presidential campaign, but neither Pitt -- who has a residence in New Orleans' French Quarter -- nor Bing has been able to forget that so much of a major American city still lays in ruins.)

"The plan is to start with 150 homes," Pitt told a gathering of reporters and residents on Monday. "But there's no reason why we can't do a thousand homes, or 10,000 . . . . We can make this happen, but we all need to join together to do this."

He added: "It will be great to see barbecues in the backyards and kids riding their bikes on the streets again."

Pitt hopes to break ground this spring on the first homes, all of them eco-friendly and built to withstand the elements -- some will even float. He also been meeting with former residents of the area, which was bulldozed after the hurricane, to urge them to return.

"We're going to need the help of the American people," said Pitt, who has spent long days at the site this week with Jolie and their children. "Each house will cost an average of $150,000 to build. People could donate $150,000 or $15. Every little bit counts. For every $150,000 that comes in, we're talking about putting a family back in a house."

The launch was marked by the unveiling of 150 bright pink canvas structures in the shape of houses looking like large Monopoly pieces and meant to remind the public that much work needs to be done.

"I asked one of the long-term residents, what do you think about what we're doing with the place? He said, 'Well, it looks a lot better around here than it did last week.' So why is it pink? That's the first question I get. Some people say it's to represent little pink houses, the American dream, the idea of getting a job and raising a family and sending your kids to school and all that was destroyed and what can be again."

But there are other reasons for the bold color. "My thinking is, it's because pink screams the loudest, it says people are coming back."

Pitt worked with a lighting specialist to illuminate the faux pink houses at night. Easily spotted from the main bridge over the Industrial Canal on the edge of the Lower 9th Ward, they glow like Christmas lights. "To me it represents the warmth of the families that lived here before, and who will live here again," he said. "To me, it's quite poetic and beautiful to behold."

The actor also unveiled the project website: www.makeitrightnola.org. Users will be able to "walk" through houses and view the home designs, which were produced by 13 teams of architects, including Thom Mayne, David Adjaye and James Timberlake. The website also allows visitors to "select" which items in the house they will support with their contributions.

The Pritzker-winning Mayne, who designed Los Angeles' new Caltrans building, said he has been in awe of Pitt's efforts.

"He has shown that a single person can come in with a vision and do something that the feds could not accomplish after two years of trying," said Mayne, who was in New Orleans for the unveiling. Pitt acknowledges that he's also satisfying a deep personal need. "Since I was a kid, I've been fascinated with buildings. I believe in their power as great social works of art. I just have such respect for the dreamer, the builder."

Pitt and his colleagues hope to demonstrate that housing is more than an art. As the old saying goes, "Charity begins at home," and Make It Right is out to prove that sometimes it begins with a home.