“I like to think that the difference between your average adult learning center and the Learning Annex,” its founder and president, William Zanker, said, “is like the difference between a school cafeteria and a hot restaurant.” That, or the difference between knitting classes or pet-grooming lectures and seminars led by Russell Simmons, Sarah Jessica Parker, and Donald Trump.

Mr. Zanker, who 25 years ago started the Learning Annex out of his studio apartment, is as loud, bold, and insistent as the lime-green walls of his corner office on West 37th Street. With the help of a devoted staff, he has spent the past several decades schmoozing, bargaining, wheeling, and dealing with the press, celebrity agents, and investors in order to revolutionize adult education. Once a decidedly un-sexy business (think unemployed 30-somethings hoping to break into screen-writing and housewives looking to improve their purling skills), the Learning Annex has evolved into a full-fledged corporation that seems to exert a magnetic pull on celebrities.

At 24, the New Jersey-born Mr. Zanker returned from Jerusalem, where he had gotten a degree in political science at the Hebrew University. Upon returning to America, Mr. Zanker enrolled in a film course at the New School. When his father broke the news that the family wouldn’t keep signing the checks, Mr. Zanker decided to set up a small business. The Learning Annex was bankrolled with his Bar Mitzvah money.

Initially, Mr. Zanker envisioned it as an informal forum wherein experienced film instructors could share their knowledge with aspiring filmmakers. But his girlfriend at the time, a pottery teacher, convinced him to expand the curriculum to include other disciplines. Before long, The Learning Annex became a successful, for-profit educational institution.

In 1991, Mr. Zanker sold the company, which he later reacquired. During his 10-year extended vacation, he started a chain of walk-in massage parlors, the Great American Backrub, and founded a Web-based learning company. In addition, Mr. Zanker and his wife traveled around the world. His three children grew up and were home schooled on the road while he and his wife “hung out” in fancy hotels. “I lived like a rock star,” he said.

Mr. Zanker put on the brakes in 2003, settled back into suburban life in Chappaqua, N.Y., and bought back the Learning Annex. “After 10 years, it hadn’t advanced at all. It was still a ‘butt in seat business,’ just live seminars.” Mr. Zanker said, “I thought, this is a brand that has huge name recognition that’s being underutilized.” Perhaps more viscerally, Mr. Zanker explained, “It was my baby – and I thought it could be something bigger.”

In the last three years of Mr. Zanker’s leadership, his “baby” has certainly grown up. “Since 2001, we tripled the business.” In addition to developing a book series, audio tapes, the Learning Annex has added branches in Los Angeles, San Francisco, San Diego, Minneapolis, Chicago, and Seattle, as well as six locations in Canada.

More importantly, Mr. Zanker has changed the core raison d’etre of his company. “We call what we do here ‘edu-tainment.’ We don’t want to be considered a school.” And with the glamour of boldface names, attendance has skyrocketed – now more and more luminaries are willing to listen to Mr. Zanker’s requests for their time.

So, what exactly do these celebrities teach? In 2003, Lizzie Grubman led “How to Succeed in Public Relations and Image Marketing.” Upcoming lectures include “Land a Great Job in Advertising” with Donnie Deutsch and “How to Shoot Your Own Live Adult Video” with adult entertainment superstars Joe Gallant and Jeff Stella – according to the Learning Annex course description, this seminar “will include a live 2-woman scene.”

Indeed, every classroom personality is larger than life. “If you’re just a teacher, we don’t want you,” Mr. Zanker said bluntly.

So, how does Mr. Zanker lasso the stars? “In the old days, when we didn’t have a lot of money, we got celebri ties through guilt. I’d tell them, ‘Listen, you’ve made it – now give back to society.” Mr. Zanker recalled Harvey Weinstein as a particularly difficult case. “I whined and whined and whined to him, ‘You’re so f-ing big, you can give an hour of your time.’ Because, for most of these guys, money is irrelevant.”

Irrelevant to everybody except Mr. Trump. In January, The real estate mogul agreed to give three real estate seminars in New York, Los Angeles, and Chicago for $1 million a class (more than $16,000 a minute). “I didn’t have to guilt him. With Donald, it was a pure business deal,” Mr. Zanker said. In fact, Mr. Trump wanted more money, but Mr. Zanker bargained him down. These engagements were settled hot on the heels of the wildly successful wealth-building seminar that Mr. Trump gave in 2004.

Despite Mr. Trump’s giant success with the company, he didn’t come easily. Indeed, it took 10 years of badgering phone calls to get Mr. Trump on board.” “When a celebrity says ‘no’ to us, we translate that into ‘not yet,’ Mr. Zanker said.

In describing his business model, Mr. Zanker likens the Learning Annex to a 3-dimensional US Weekly of sorts. “A magazine is flat. It’s a passive instrument. You read it, but can’t really take anything out of it. There is no reality. You can read an article about Joe Torre, but can you ask him a question? No. At the Learning Annex you can.” The Learning Annex strives to recreate the immediate gratification of reading a glossy tabloid in its classes. Seminars are high-energy, catered to those with short attention spans: They only meet once a week and they’re as much about celebrity-ogling as they are about gaining knowledge or skills.

But there is a deeper level, Mr. Zanker insisted: “We believe in changing people’s lives.” For about 50 bucks, students get the chance not only to be in the same room as one of their idols, but they can ask questions, and maybe give them a script, demo, or exchange a handshake.

Those who aren’t blessed with cushy connections can get their foot in the door at notoriously exclusive industries – for a price, of course. “When Clive Davis came,” Mr. Zanker said, “he said he would listen to at least one minute of every demo tape. The class stood up and screamed. I get off on that. The students are psyched, Clive Davis is happy, and I get money. Everybody won that night.”