Lobbyists Tony and Heather Podesta are working the crowd at a reception in an art museum for big donors to House Democrats. He schmoozes with Rep. Anna G. Eshoo (Calif.) and huddles with Rep. John P. Murtha (Pa.). She makes plans to go shopping with Christine Pelosi, the daughter of House Minority Leader Nancy Pelosi (Calif.), and the chief of staff to a Democratic member of the House.

And then they're off. Jumping into a chauffeured Cadillac, the husband-and-wife team dashes to another reception, this one in an elegant restaurant for big donors to Senate Democrats. Before the night is over, they will attend two dinners and three more receptions, carrying the flag for cable giant Comcast Corp., defense industry leader Lockheed Martin Corp. and other clients. And this was just Monday, Day One of the four-day Democratic National Convention.

The Podestas are involved in what amounts to the only real work going on at the convention -- the nonstop currying of favor of elected officials by the most powerful interests in the country. They are among thousands of lobbyists who have descended here to host hundreds of events on behalf of their clients.

Thanks to a loophole in campaign finance laws, a presidential convention is the one place where corporations and labor unions can still spend with abandon to influence holders of high office. Lobbyist-paid festivities are nothing new during presidential conventions, of course. But this year they are more numerous and lavish than ever.

Since unlimited donations to the national party committees were banned in 2002, the budgets of the Democratic and Republican conventions have skyrocketed. According to the nonpartisan Campaign Finance Institute, the cost of this year's presidential conventions will top $103 million, nearly twice what it was four years ago. The host committee of the Democrats' convention alone has collected more than $39.5 million, and that is before counting the millions of dollars for private parties.

Corporations, trade associations and labor unions -- all now barred from contributing to political parties -- have turned conventions into multimillion-dollar spending sprees, capitalizing on exemptions from federal campaign finance law and congressional gift bans to wine and dine all manner of elected officials, from top-ranked members of Senate committees to backbenchers in state legislatures. From the perspective of narrow interests, conventions are the one remaining way they can legally put money behind federal officials without running afoul of the ban on unlimited "soft money" donations.

"Conventions are the last oasis," said Democracy 21 President Fred Wertheimer, a longtime critic of campaign finance laws.

And the money has poured in. Every day, from 7 a.m. to 2 a.m., breakfasts, brunches, luncheons, cocktail parties, dinners and post-convention fetes are convened to honor senior Democratic officials. These events range from a simple breakfast meeting with coffee, fruit and bagels in a downtown hotel to the rental of a cruise ship docked at Boston Harbor or a golf tournament on the outskirts of Boston.

Over a week's time, at least 265 such events are listed on public and private schedules handed around by lobbyists and major contributors to the party. But that is clearly an understatement. There are so many parties here that even high-profile lobbyists such as the Podestas can't attend every one to which they are invited.

"I'm consistently triple- and quadruple-booked for the lunch and dinner slots," says John F. Jonas, a top lobbyist at the D.C. law firm Patton Boggs LLP.

On Tuesday, the D.C. lobbying law firm Akin Gump hosted a brunch for New Mexico Gov. Bill Richardson at the Algonquin Club; the American Gas Association paid for a luncheon for Sen. Byron L. Dorgan (D-N.D.); and the Wine and Spirits Wholesalers of America Inc. underwrote a "toast" at Saint, a restaurant-lounge, for Sen. Max Baucus (D-Mont.), who would assume the chairmanship of the Finance Committee if Democrats win back the Senate.

The possibility that Democrats might take back the White House or regain power in Congress has fueled all the lobbyists' partygoing. "They're covering their bets," says Larry Noble, executive director of the nonpartisan Center for Responsive Politics. "Corporations are very pragmatic; they are always counting on the possibility of change."

What's more, the lobbying community has not held back when Democrats have asked for funds. Fifteen corporations, unions and foundations have each given at least $1 million to the Boston host committee, including Bank of America Corp., International Business Machines Corp., Gillette Co., Verizon Communications Inc. and the Service Employees International Union. Another 15 have given from $500,000 to $1 million. In 1992, the Democrats did not accept more than $100,000 from any single donor.

Even ardent proponents of tough regulation of campaign contributions tend to jettison their qualms when they get to conventions.

On Monday, Sen. Richard J. Durbin (D-Ill.) emerged from a $19,000 Union Oyster House luncheon given in his honor by the Chicago Board Options Exchange, the Chicago Board of Trade and the Chicago Mercantile Exchange to say accepting the gift was "totally consistent" with his stand on campaign finance.

Durbin, an original co-sponsor of the McCain-Feingold campaign finance law, defended the luncheon as an extension of his "day-to-day contact with business from my state," which he called "an important part of my job." The attendees, he added, are "diverse friends and supporters and people from the business community."

"It's hospitality at the convention, and I think that's part of the experience," Durbin said.

Under Senate ethics committee rules, if any one of these businesses wanted to take Durbin out to dinner, the most it could pay for his meal is $49.99. The Senate, however, added 23 exemptions to this relatively strict rule, including "free attendance at a widely attended event that is officially related to Senate duties." This opened the door to such events as Durbin's lunch here.

Like many lobbyists, the Podestas have dedicated their stay in Boston to enhancing the experience of their clients and the lawmakers they want to influence. After breakfast on Monday, they gave each other a high-five when they realized they had cadged 14 tickets for distribution. "Not bad for a morning's work," Tony Podesta said with a wink.

"That's the difference between a good lobbyist and a great lobbyist -- concierge service," Heather Podesta said.

Neither Tony Podesta, who is co-chairman of PodestaMattoon, nor Heather Podesta, a partner in Blank Rome LLP, asked anyone for a legislative favor all day. Instead, they tried to pave the way for future pleas by glad-handing amiably and paying the tab as often as they could.

Tony Podesta and his on-site staff of six helped plan nearly 20 events throughout the week. These included a National Association of Broadcasters dinner for Sen. Patrick J. Leahy (D-Vt.), a Qualcomm Inc. reception for Sen. Charles E. Schumer (D-N.Y.), a Textron Inc. lunch for Sen. Mary Landrieu (D-La.) and breakfasts by Lockheed Martin for both the North Dakota and New York delegations.

At each affair, the Podestas took care to make a splashy entrance. Their job was, after all, mostly to be seen. Tony Podesta wore fire-engine red shoes along with his trademark Italian suits and bright tie. Heather Podesta also worked purposefully at standing out. On Sunday night, she wore turquoise and red. On Tuesday, she was in red only. "We want people to be able to find us," Tony Podesta said.

But they aren't merely show horses. So far this year, the Podestas have collected more than a million dollars for Democrats, much of it from lobbying clients. They're well known for holding fundraising dinners in their art-filled Washington home, which feature pasta cooked fresh by Mary Podesta, his 86-year-old mom.

In addition, Tony Podesta is more than a supplicant to the Democratic hierarchy -- he is also a member of it. Podesta serves as Sen. John F. Kerry's volunteer campaign manager in Pennsylvania. Podesta is the brother of John Podesta, the former Clinton White House chief of staff and now the head of a liberal think tank.

Lobbying critics may disapprove, but the Podestas' methods clearly work. At the Connecticut delegation's breakfast Monday -- an event sponsored by Genzyme Corp., a PodestaMattoon client -- Heather Podesta got a hug from Sen. Christopher J. Dodd and Tony Podesta got a big compliment from Clarine Nardi Riddle, chief of staff to the state's other U.S. senator, Joseph I. Lieberman.

"He's close to Joe," she said. What more could a lobbyist hope to hear?

Democratic lobbyist Tony Podesta, right, confers at the convention with Rep. John P. Murtha (D-Pa.) and Gabrielle Carruth, one of Murtha's aides.