THE EXPERT: Gene Levin ’56, physics professor at the City University of New York, author of The Best Jokes and Stories and How to Tell Them (available through iuniverse.com), and veteran of decades of helping students chuckle through their fear of science.

THE QUESTION: How can I tell a joke that makes people laugh?

THE ANSWER: Levin’s number one comedic rule is to never forget the punch line. His second? Don’t ask if your audience has heard the joke before. (“Who’s to say they wouldn’t enjoy hearing it your way?” he says.) Know your material well so you don’t stumble or hesitate, lest your fumbling distract from your story’s spell. “You want to use details to tighten your listener’s anticipation like a spring, until bing!, you hit the punch line and everything releases,” Levin says. To ratchet up that spring, Levin says, “Launch yourself into the stories. Use accents, hand-motions. You need to be a ham.” But not an oaf. Don’t dominate conversation; slip your stories into the normal ebb and flow of talk. And respect your audience. Levin is fond of “salty” material (heard the one about the amorous mouse and the elephant?), but not when he’s with kindergarten teachers. “The funniest stories,” the professor counsels, "are built on simple human recognition."