U.S. Reps. Edward Markey and Stephen Lynch joke with the crowd during the annual St. Patrick's Day breakfast in South Boston, Sunday, March 17, 2013. (Steven Senne/AP)

The race for the U.S. Senate descended on the St. Patrick's Day breakfast in South Boston Sunday, giving the candidates an opportunity to show off their sense of humor.

The breakfast is home turf for Congressman Stephen Lynch, of South Boston. When he was Southie's state senator, he hosted the event. On Sunday, it was his chance to be gracious to his opponent in the Democratic primary, Congressman Ed Markey, of Malden — and he was. Lynch went over to Markey at one point to talk to him.

And then it was time to try to be funny. Lynch went first.

"After Ed Markey announced his candidacy for the U.S. Senate, four elected officials from his district announced their candidacy for his seat, but when I announced my candidacy for the United States Senate, not a single elected official in my district announced their candidacy for my seat. So to all my elected officials in my district, I want to thank you for your confidence," Lynch said.

Markey recognized that he was in Lynch's territory.

"I wanted to introduce you to my South Boston coordinator, but he is in a witness protection program at an undisclosed location," Markey said. "That's about the extent to which I can get support here in Southie."

Sen. Elizabeth Warren spoke at the annual breakfast Sunday. (Steven Senne/AP)

U.S. Sen. Elizabeth Warren took digs at the Republican candidates in the race, including state Rep. Dan Winslow, of Norfolk.

"I advise everyone to pay very close attention to Dan Winslow's platform," Warren said. "He has a 100 percent ranking from the gun lobby and he's for the legalization of marijuana. He wants us armed and stoned."

Winslow was the only Republican Senate candidate invited to the event. He said he was asked to speak but declined. Still, as the event was getting under way, he proved to reporters that he did come armed with jokes.

"Elizabeth Warren was finally right," Winslow said. "Last year, she went around the state saying, 'People are getting hammered. People are getting hammered. People are getting hammered.' As I look around Boston today on South Boston on St. Patrick's Day, people are getting hammered."

The other two GOP Senate candidates — Cohasset private equity manager Gabriel Gomez and former U.S. Attorney Michael Sullivan — were not invited to the event. Organizers say it was because they didn't ask, to which a spokeswoman for Sullivan replied that it's "quite uncouth to ask for an invitation anywhere!"

Last week was a rough one for Gomez, the newcomer to politics. He promised at a forum that he would release the letter (PDF) he wrote to Gov. Deval Patrick asking the governor to appoint him as interim senator when John Kerry resigned. True to his word, Gomez released the letter, and when he did opened himself up to criticism for reaching out to a Democratic governor.

At the breakfast Sunday, Warren took a dig at Gomez.

"I'm sorry that I don't have any advice for Gabriel Gomez, because I always support my fellow Democrats," Warren said.

Gomez said he and Sullivan probably did not get invited to the breakfast because they probably have funnier jokes. Gomez told his own at the Republicans' breakfast in Scituate instead.

"The one that got the best laugh was: Everybody knows I'm a Navy SEAL, and they assume that I'm some kind of really tough guy, but I'm just like everybody else," Gomez said in a phone call to WBUR. "I wake up every morning at 5:30. I read the paper. I eat a couple of snakes, I get water-boarded and I go to work."

In Massachusetts on St. Patrick's Day, part of the work of a politician is to brave the audience and take the chance that they may not laugh at your jokes.