New York ? Who knew? Martha Stewart has quite the poker face.

On today’s edition of her syndicated television show, “Martha Stewart Living,” the star stands in front of a giant to-do list.

“April is such a busy month,” she says. “Just look at all there is to do.”

For instance, she must lecture slacker chickens on better egg laying. The north side of the Empire State Building needs cleaning. And she has to send her tax returns to the calligrapher (“I never get audited,” she confides).

When daylight savings time begins April 7, she’ll replace her clocks and VCRs.

“And buy a new car,” she says, “because I can never figure out how to change those darn clocks.”

April Fools, of course.

It’s quite funny. Who better to poke fun at Martha Stewart than Martha Stewart? As befits a billionaire businesswoman with a sprawling empire, her humor is skillful and efficient.

She goes on to instruct viewers on the proper way to prepare a glass of water, using aluminum ice trays available on eBay. Stewart’s gardening segment then discusses the care of a bottle tree, also known as the morning-after plant. She tends to one “bud” Â plucking an empty Budweiser bottle from a wooden stem.

“A lot of people don’t see my sense of humor,” Stewart said later. “Generally, I’m pretty straightforward on the television show because it’s my teaching approach. But I have a very good sense of humor, (although) sometimes it’s maybe too sophisticated for people. But I like poking fun at myself.”

Controlled humor

Sure she does, said the author of an upcoming book on Stewart  as long as she can control the humor.

“I think she would be terrible at a Friars Club roast,” said Christopher Byron, whose book, “Martha Inc.: The Incredible Story of Martha Stewart Living Omnimedia,” comes out next week.

“I don’t think she wants to be subjected to spontaneous, rough humor about her,” Byron said. “If she could prepare the jokes first, she’d be great at it.”

Martha humor has become something of a shadow industry. There’s been a series of parody books, beginning with “Is Martha Stuart Living?” the misspelling intentional to deter humorless lawyers. Two short-lived television series were loosely based on her. Ana Gasteyer of “Saturday Night Live” is a regular impersonator.

And the Internet is an endless repository. One Web site lists 494 “ways to kill Martha Stewart.” One contributor suggests: “lock her in a room with nothing but a bottle of Yoo-Hoo and a bowl of Velveeta-covered Spam.”

Stewart’s an easy target because she makes look easy what most women find next to impossible, said Maria Pope, executive producer of David Letterman’s “Late Show.”

“You like to play with perfection,” she said.

Yes, Martha sees it all. She’s a particular fan of New Yorker cartoonist Roz Chast, who in one piece titled “Martha Stewart takes over the universe” has her laying out fresh flowers for brunch on Pluto.

“Some people do it well and some people do it terribly,” she said. “‘Saturday Night Live’ is always kind of fun, even if a little off-color. At least it’s funny. If it’s funny and done non-maliciously, it’s fine. Being parodied, as being copied, is the highest form of flattery.”

Poking fun at herself is also a good way to take the pressure off fans who watch her with anxiety, Stewart said. Maybe they’ll enjoy seeing a four-course dinner prepared on TV and not feel guilty about popping something in the microwave.

“If I can make fun of a glass of water, it just makes viewers feel, ‘She’s OK,”‘ Stewart said. “They’ll laugh, and they’ll think: ‘Don’t take it all so seriously. Do it when you can, do it when you have time, do it when you’re in the mood.”‘

Finding an advantage

As always, there could be a business advantage to this.

Ratings are down for “Martha Stewart Living,” which began in 1993. She’s lost half her audience in the past four years, said Marc Berman, an analyst for Media Week Online.

Part of it is because daytime TV viewing is off in general, but there’s also a sense of “how many times can you watch her making curtains out of a dress?” he said.

“The more she’s able to laugh at herself, the better she’s going to be,” Byron said.

Stewart’s sense of humor is no surprise to the folks at “Late Show,” where she’s been a frequent straight-woman for Letterman, Pope said.

“She is one of our favorites,” Pope said. “She always comes ready to play and have a good time. She’s game for anything, which we like. And she always leaves the dressing room cleaner than she found it.”