A goose waddles into a department store and buys a tube of pink lipstick. "That'll be $5.99," says the cashier. The goose replies: "No problem. Put it on my bill!"

Yup, that's a real groaner. But brace yourself. The YOU Docs have plenty more kooky humor ahead. (Up next: Our favorite corny doctor joke.) We're trading in our stethoscopes for joke books today because we're determined to get you to giggle, guffaw or at least crack a wicked little smile. The reason? New research shows that exercising your unique sense of humor is the easiest way ever to add years to your life.

A man with a cucumber in his ear, a carrot in his nose and a tomato in his eye walks into the doctor's office. He says: "Doc, I'm not feeling well. What's wrong with me?" The doctor replies, "First of all, you're not eating right. ..."

But seriously, folks. Laughter's great medicine. In this new Norwegian study, researchers who tracked the health of 70,000 people found that those who scored highest on sense-of-humor tests were twice as likely as dour sorts to still be alive -- and laughing -- seven years later. You didn't have to be the type that laughs at the drop of a hat, either. All sorts of humor styles boosted survival. "A twinkle in your eye can be more than enough," notes lead researcher Sven Svebak of the Norwegian University of Science and Technology. In fact, everybody who scored in the top half humorwise got at least a 20 percent longevity boost.

What's behind humor's life-prolonging powers? For one thing, laughter is a miniworkout. Ten to 15 minutes of mirth burns up to 40 calories and exercises your abdominal muscles. And that doesn't count what Dr. Mike does nightly -- no, not that! He watches "Daily Show" while on the treadmill. A good belly laugh also boosts your immunity, motivating natural killer cells in your bloodstream to work harder. In one study, watching a funny movie relaxed the endothelium -- the fragile inner lining of your arteries -- enough to boost blood flow by 15 percent. Laughter eases stress and reduces levels of the high-anxiety hormone, cortisol. In people with diabetes, it can even help keep blood sugar lower and steadier.

Then there's resilience. Laughter helps you build and maintain friendships, eases fears and gives you a hand at coping with whatever life throws your way. It may also thwart the flu and protect against cancer.

Q: Why are cats such bad dancers?

A: They have two left feet.

Think your sense of humor needs a little training (or that we YOU Docs need better material)? Feel like you're not laughing enough these days? These steps can help you lighten up:

Get your daily quota of yucks. Check in with yourself at lunch time: Have you chuckled today, or maybe even gotten that tingly "this is hysterically funny" feeling? If not, do something about it. E-mail or call your funniest friend. Plan to watch your favorite sitcom or wise-cracking commentator tonight. The Web is loaded with joke sites, bookstores are brimming with humor books, video stores offer thousands of comedies and stand-up comic shows. Make it a point to learn at least one new joke a week, then tell it to your friends (hey, they need a yuck, too).

See the humor in your life. You took the stray cat you rescued to be spayed and discovered that she's a he? Trade funny stories: Make it a habit to ask friends and family about the most ridiculous thing that's happened to them today, this week, this month.

Discover what really tickles your funny bone. Your sense of humor is as unique as your fingerprints, so stop laughing at what you think you ought to find amusing and do a little research into what really hits your sweet spot. Try watching, reading or listening to types of humor that are new for you. You may discover you prefer political humor or cowboy jokes, martini-dry wit or a really bad knock-knock. Like this one:

Knock-knock

Who's there?

Freddie!

Freddie who?

Freddie or not, here I come!