LAST JUNE, ON A WARM NIGHT in downtown San Francisco, Laurie got serious with a speech at a dinner held in conjunction with the United Nations World Environment Day, a 20-minute introduction to the night's main speaker, Al Gore. The audience included celebrities, industry execs, and politicos—from actress Rosario Dawson to Google cofounder Sergey Brin. Laurie, wearing a midnight-blue Prada evening dress, used cocktail hour to schmooze with the crowd, chatting with House Minority Leader Nancy Pelosi, from California, and Pete McCloskey, that state's former Republican congressman. She was glowing when she took the stage.

"Global warming is an economic problem, a national-security problem, and a public-health nightmare," she said. "Its solutions can no longer rest on the shoulders of the environmental movement alone. Right now, new groups and interests are engaging on this issue—including evangelicals and right-wing hawks—but they are working separately. The true force of this human-rights movement is not yet being felt. We need one giant act of community to unite us."

Laurie, in fact, is the rare environmental spokesperson who's focusing on big-picture strategy. Fewer than 1 percent of Americans are currently members of environmental organizations—a good indication that the movement's message is reaching only a select few.

Green groups have typically avoided sharing resources, but Laurie has convinced 20 of them, including Conservation International and the Sierra Club, to promote her Web site among their combined ten million members. Her list of "marchers" so far includes politicians, religious coalitions, hunting and fishing groups, soccer moms, and utility executives—that alone represents a grassroots coalition bigger than most others established on climate change.

Still, there's no clear sign that Laurie's march will be anything like the tide-turning force she envisions. Eight months before Earth Day, she had reeled in 110,000 participants—only one-tenth of her target number. And if her fall marketing campaign does help summon a million-plus voices of protest, will a collection of names really make much difference? It's a tough question, but Laurie's not about to sit still long enough to ponder it.

BACK AT HER bathroom-cum-office, Laurie makes time between business calls for personal chats with friends. At one point, Larry checks in, too, and finds that his wife has a surprise.

Laurie: Honey, you're gonna kill me.

Larry: Now what?

Laurie: Just keep an open mind, OK? I gave away your Prius.

Larry: You what?!

Laurie: Well, not your Prius—the one you drive on Curb. I offered it up as a prize for this contest that MTV is doing to get its viewers to join the march. Isn't that exciting! MTV loves the idea: Thousands—maybe tens of thousands—of people will join just because they have a shot at getting the Curb car! (silence)

Laurie: Larry... honey? I had to! We're stopping global warming!