Ann Romney on the "Tonight Show with Jay Leno" Tuesday. (NBC Universal Media/Reuters)

Funny line, huh? Big laughs from the audience Tuesday night because it was probably the first time they’d heard the joke. But not the first time she’d told it: She did the same bit two weeks ago on “Kelly and Michael,” at the Tampa convention and at a campaign stop this spring.

Like stand-up comics, politicians and their spouses use jokes and one-liners to warm up an audience, and then recycle the best ones into campaign appearances. Staffers can recite them by heart, but crowds eat them up.

A few go-to favorites:

President Obama loves this story so much he tells it almost every day — including Thursday in Virginia Beach.

President Obama at a campaign event last week in Woodbridge, Va. (Carolyn Kaster/AP )

Obama’s other crowd pleaser: “I’m not a perfect man. Ask Michelle.”

Mitt Romney may not be a naturally funny guy, but he has one line guaranteed to get laughs. When he’s touting his business experience and private-sector bona fides, he makes a point of saying how little time he logged on the public payroll: “I only spent four years as a governor. I didn’t inhale.”

Romney dropped the line into a Republican primary debate a year ago and used it at the Conservative Political Action Conference (where the poke at Bill Clinton was a big hit) and other whistle-stops this year.

Paul Ryan at a campaign stop in Fort Collins, Colo., Wednesday. (Ed Andrieski/AP)

Surprisingly, Joe Biden hardly ever uses the same one-liners twice. Instead of saying funny things, he says things funny. “Folks, I can tell you I’ve known eight presidents, three of them intimately,” he told a Detroit audience in August. And no, that wasn’t supposed to be a joke.

Ditto for first lady Michelle Obama, who rarely cracks jokes or strays from her prepared remarks. Her funniest turn this year was on David Letterman’s Top 10 “Fun Facts” about gardening. Her No. 1 tip: “With enough care and effort you can grow your own Barack-oli.” And then she held up a giant green stalk with the president’s face.

Hey, no one ever said comedy was easy.

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