The policy matters that have sparked sharp divides between Democrats and Republicans were not on the agenda.
"We did not get into the substantive issues, whether it's Netanyahu, DHS funding. This was a get-to-know-one-another, get-to-learn-about-one-another," said Sen. Charles E. Schumer (D-N.Y.).
Senators could sit wherever they wanted -- provided, of course, that they plopped down next to someone from the other political party. Schumer sat between Sen. John Thune (R-S.D.) and Richard Shelby (R-Ala.).
Sen. Mark Kirk (R-Ill.), who was elected in 2010, said the lunch started with stories from more senior members about about a time when the Senate was a more cooperative place, then moved to getting to know the freshman class better. He said Sen. Orrin Hatch (R-Utah) spoke about his partnership with late-senator Edward M. Kennedy (D-Mass.).
The senators dined on a bipartisan menu (naturally) that featured Maine lobster provided by Sen. Susan Collins (R), Virginia ham from Sen. Mark Warner (D) and a kosher alternative.
There were signs of bonhomie, if only briefly, all over the third floor of the Russell Senate office building where the lunch was held.
Sen. Jerry Moran (Kan.), who led the effort to retake the Senate as chairman of the National Republican Senatorial Committee last cycle, exited the lunch with his hand on the shoulder of Sen. Jon Tester (Mont.), the man heading the Democratic effort to win it back in 2016.
For Minority Leader Harry M. Reid (D-Nev.), Sen. Lindsey O. Graham (R-S.C.) wasn't "the senator from South Carolina," as is customary on the Senate floor. He was simply "Lindsey." And to Graham, Reid was just "Harry."
Sen. Maria Cantwell, a liberal Democrat from Washington, chatted after the meeting with Dan Sullivan, a conservative Republican from Alaska.
The idea for the lunch sprung out of a bipartisan getaway Sens. Jeff Flake (R-Ariz.) and Martin Heinrich (D-N.M.) embarked on last year on a tiny island in the Pacific Ocean.
"You asked if we cooked up this idea on the island. That was about all we could cook up because we couldn't light a fire," said Flake.
Senators hope to make the lunch a regular monthly occurrence. Still, the inter-party discord that has divided them didn't seem far away, even in their midday oasis.
After lunch, senators headed to a vote on a GOP-backed Department of Homeland Security Funding bill. Democrats, as they had a day earlier, blocked the bill.
Entering the meeting, some Democrats talked about a possible boycott of next month's address before a joint meeting of Congress by Israeli Prime Minister Benjamin Netanyahu. Netanyahu's appearance was arranged by Republican leaders.
Will they talk about substance next time?
"We don't know. We'll decide," said Schumer.
Even though the lunch produced no sweeping compromises, it didn't make things any worse, according one longtime senator.
"Can't hurt. Can't hurt," said Sen. John McCain (R-Ariz.).