Last Wednesday night, while Senate leaders tangled in a partisan showdown over new ethics rules, hundreds of Capitol Hill types were putting party differences aside to enjoy some of the best food and drink the city has to offer.

Filing into Charlie Palmer Steak, lawmakers, lobbyists and staff were greeted by low lights, and from the dance floor, the foot-stomping rhythm-and-blues of Shemekia Copeland. Bars and buffet tables lined the walls. Former Speaker Dennis Hastert (R-Ill.) showed up early on. Later, freshman Rep. Steve Cohen (D-Tenn.) could be seen sitting on a banquette, tie flipped over his shoulder, digging into a plate of steak and fries. Later still, House Democratic Caucus Chairman Rahm Emanuel (Ill.) was spotted in a hallway, chatting on his cell phone.

Though lawmakers and staff enjoyed the evening for free, the party, billed as a welcoming event for new Members of Congress, did not come cheap. Tyson Foods, Wal-Mart, PepsiCo, and FedEx each chipped in $10,000 to cover the expense. Other sponsors included the National Association of Broadcasters, Microsoft and the Distilled Spirits Council of the United States. Their names were printed on tickets party-goers wore around their necks.

Three weeks into the 110th Congress, lawmakers in both chambers have taken strides toward passing what public-interest groups hail as the most significant ethics overhaul since the post-Watergate reforms. Even as work on those packages continues, a new reality governing interaction between Congressional and corporate professionals is taking shape.

The House banned gifts and meals from lobbyists and the companies they represent, and the Senate moved toward following suit last week. That means the days of lobbyists treating lawmakers to intimate steak lunches may be a thing of the past.

But nearly two dozen exemptions to the gift rules survived the latest round of reforms, including one that allows lobbyists to mingle with lawmakers and staff and pay for their steak, among other things, on their dime — as long as it occurs at a big function.

As one corporate lobbyist surveying the scene last week wryly noted, “I think you’re going to see a lot more ‘widely attended events.’”

Lobbyists and event planners said the parties are likely to become more frequent, as K Streeters look for new ways to pay for social time with decision makers that formerly occurred over meals and on privately financed trips.

“Widely attended events will be the model for the future of any sort of interaction with Members, because everything else is restricted,” said Ryan Costella, president of Volta Live, the marketing-through-entertainment company that put on the Charlie Palmer event.

To qualify as a widely attended event, the House and Senate ethics committees require that at least 25 non-Hill employees are expected to show up, Members and staff are invited by a sponsor, and attendance has something to do with their official duties.

Already this year, the events have proved a popular way for lobbyists to get together in a friendly atmosphere with important contacts on the Hill.

They filled up the first week of the year with parties to honor new lawmakers. Holland & Knight threw a bash for Florida Reps. Vern Buchanan (R) and Ron Klein (D); Honeywell hosted the Iowa delegation in its offices; John Jonas of Patton Boggs co-sponsored a party honoring Sen. Ben Nelson (D-Neb.); and Patrick Murphy of mCapitol Management welcomed 200 people to his home for newly minted Sen. Jon Tester (D-Mont.).

The House ethics committee issued a memo in mid-December reminding lawmakers that lobbyists could not pick up the tab for their official receptions.

But, it noted, “free attendance at a swearing-in related event sponsored by an outside organization generally is permissible under the ‘widely attended’ event provision of the gift rule” as long as the standards of the exemption were met.

Lobbyists still expect campaign fundraisers to play a major role in the off-the-clock time they spend with lawmakers, and there is no sign the furious pace of those events will slacken in the wake of new ethics rules.

On Jan. 4, the same evening that Speaker Nancy Pelosi (D-Calif.) shepherded a rules package through the House banning gifts and travel from lobbyists, hundreds of K Streeters coughed up at least $1,000 to attend a party in Pelosi’s honor. Packed into the National Building Museum, they took in performances by Wyclef Jean, Tony Bennett and the Grateful Dead. White cocktail napkins along the buffet tables had the words “Speaker Pelosi” emblazoned in gold.

And the events keep coming. This morning, Rep. Stephanie Tubbs Jones (D-Ohio), chairwoman of the House Committee on Standards of Official Conduct, is getting together with lobbyists for a “Manicures and Muffins Breakfast” at Capitol Nail Salon, which is just blocks from the Capitol.

A week from today, lobbyists eager to show support for the new House majority have seven events to choose from, including one for Judiciary Chairman John Conyers (D-Mich.) at a Verizon Center suite to watch the Washington Wizards take on the Detroit Pistons.

Some lobbyists have speculated they can continue to wine and dine key Hill allies — as long as they hand them a campaign check at the end of the meal and count its cost against the donation —but legal specialists said the ethics committees will frown on the practice.

“The ethics committee hasn’t had to get into those types of issues in the past, because they haven’t had to,” said Jan Baran, a campaign finance lawyer. “But lobbyists are crazy to think they can get away with it.”

Added Fred Wertheimer, president of Democracy 21, “People who think they’re just going to walk around these ethics rules are dead wrong.” He said even if widely attended events become the norm, they will remain “a different ballgame from a lunch or a dinner where a lobbyist has a Member captive.”

Already, some big-money organizations are looking ahead to the next major venue for such receptions: the national party conventions. Senators adopted a change in their ethics bill that bans groups from staging lavish parties in a Member’s honor at the conventions, and the House is expected to match it.

Nevertheless, Ken Gross, a lobbying ethics and campaign finance lawyer at Skadden, Arps, Slate, Meagher & Flom, said the ban is crafted so narrowly that corporate-sponsored parties most likely will carry on.

“The plain wording of this is not restrictive,” Gross said. “If you read this literally, you could probably find a half a dozen ways around it.”

Eric Mische, co-founder of a firm focused on event-planning for the Republican convention in Minnesota, said while parties honoring Members may be a thing of the past, companies are still looking to stage large-scale events to help advance their agenda.

“Other than the tons of money they spend, they want people to remember what it is they do, and they want them to continue to support their efforts in those areas,” he said.

As one lobbyist behind the Charlie Palmer event noted, “Widely attended events are the only place where you can have a meal or a drink or a chat. It adds texture to your relationships that you can’t get when the only contact you have is a business meeting on Capitol Hill.”

Kate Ackley contributed to this report.