It's 10 minutes before showtime, and the crowd is already spilling out the doors of San Francisco's Axis Cafe. A high-energy buzz fills the air -- until the star of the evening steps onstage and fires up his PowerPoint presentation.

A hush descends upon the crowd in the Portrero Hill venue as Terrence Deacon, a UC Berkeley biological anthropology professor, begins holding forth on Fibonacci numbers and finches. As audience members sip tomato-basil soup, they think ahead to the Q&A session, when they'll ask questions such as "What was that about the lazy gene?"

The scene at the Axis Cafe Wednesday night was part of San Francisco's monthly "Ask a Scientist" salon, where science buffs and average Joes alike gather to get the lowdown on everything from brain development and global warming to the physics of monster waves.

The combination of a casual setting that includes beverages and articulate scientists who don't assign homework seems to have struck a chord with everyone, everywhere. The "cafe scientifique" movement that began in England a decade ago has now spread to science cafes around the world, in coffeehouses, bars and even bowling alleys.

The Bay Area boasts five such salons, as well as special math and science events sponsored by Berkeley's Mathematical Sciences Research Institute, the local American Chemical Society and other groups. Last week, there was Deacon's language development talk in San Francisco, a "Darwin and Buddha" discussion in Sebastopol -- where the science cafe meets every week -- and Alan Alda of M*A*S*H and Scientific American Frontiers fame, waxing eloquent on M*A*T*H and curved space in Berkeley.

It's been a delightful, though dizzying, whirl for Juliana Gallin, the graphic designer who launched Ask a Scientist five years ago, before she had even heard of the European movement.

"I was looking for some kind of volunteer work to do just for fun," said Gallin. "I like science and I wanted to do something kind of social and interesting. This idea came up almost out of thin air."

Audiences poured in and returned the next month with friends in tow. On Wednesday, for example, less than a quarter of the audience members were newbies. The rest were a diverse crowd of devoted repeats -- men, women, fifth-graders, seventysomethings and scientists. The common denominator, says Gallin, is that they're "randomly curious."

"It's really moving to me that people come out on a weeknight to hear something interesting," she said. "One cute lady comes in on her walker every month. Some teachers bring their students."

Ten-year-old Max Adler had come over from Oakland with his dad. Systems analyst Jeff Long zipped across town after work, lured by the thought of a lecture as interesting as that last one on exoplanets.

And oceanographer Dale Robinson was back too, after hearing colleague Toby Garfield's October talk about the geography and physics behind the legendary monster waves at Mavericks near Half Moon Bay.

"It was a tag team, (Garfield) and a surfer," said Robinson. "Between them, they could explain the system really well."

The success of these events doesn't surprise Robert Osserman, who runs special projects for Berkeley's Mathematical Sciences Research Institute. Osserman hosted the institute's "Conversation with Alan Alda," as well as math-related talks with comedian Steve Martin, composer Philip Glass and the writers of The Simpsons. And his forum on Fermat's Last Theorem not only sold out the Palace of Fine Art's 1,000-seat theater, it had scalpers hawking tickets in the parking lot.

Math and science soirees are not exactly new, said Osserman. They're just new here. Any self-respecting salon hostess in Napoleonic France included a mathematician or scientist in her intellectual mix.

"People's salons all had to have a mathematician," said Osserman. "There were all kinds of prizes for mathematical essays, and Napoleon surrounded himself with top scientists of the time."

In this country, math and science's cachet has gotten a significant boost in recent years from pop culture, thanks to television shows such as CSI and Numb3rs, which features a tousle-haired math professor as an FBI consultant.

"CSI," said Osserman, "sends an undercurrent, a message that science really can be very important. "Numb3rs started out very explicitly talking about how beautiful math is. You search the first 50 years of television for very appealing, sexy mathematicians! (Now) you have this chief, very appealing character who is a mathematician."

The proliferation of science cafes plays into those interests and a passionate desire on the part of scientists and the public to explore topics that play across headlines on a weekly basis: stem cells, global warming, medicine and glitzy discoveries in the far reaches of the galaxy. According to a national survey last year, the science cafes have a ripple effect -- 81 percent of the participants had recommended science cafes to friends, and 83 percent had become so interested in the topics that they read more on their own.

Now, there's a movement afoot to spread the cafe gospel. The second national conference of cafe organizers is planned for this summer. And science cafe organizers from Berkeley, San Francisco and Lamorinda met last weekend to share tips, ideas and the results of those casual questions they ask at the start of their events -- "Where are you guys from?"

The result? Coming soon to a venue near you: Science Cafe.

Bay Area science cafes

Free science and math-related special events in the Bay Area.

EAST BAY SCIENCE CAFE

Organized by the Berkeley Natural History Museums at Central Perk, 10086 San Pablo Ave., El Cerrito. For details, visit http://bnhm.berkeley.edu/about/sciencecafe.php or call 510-642-6968. Upcoming talks include:

"Darwin and Intelligent Design" -- 7 p.m. Feb. 13. Kevin Padian, curator of the UC Museum of Paleontology, talks about Charles Darwin, one of the most revered and most reviled figures in the history of biology. What did Darwin really say? Does natural selection imply that random processes guide the history of life and that there is no meaning to existence?

"Mycology" -- 7 p.m. March 13. Debbie Viess, co-founder of the Bay Area Mycological Society, topic TBA

ASK A SCIENTIST, SAN FRANCISCO

Ask a Scientist holds salons at the Axis Cafe, 1201 Eighth Street (between 16th and Irwin) and Bazaar Cafe, 5927 California St., San Francisco. For details, visit http://www.AskaScientistSF.com. Upcoming events include:

"Phat Tuesday Physics Circus" -- 7 p.m. Feb. 5 at the Axis Cafe. Ringmaster (and physics teacher) Zeke Kossover and his sideshow scientists illustrate physical principles with a series of vivid demonstrations, including lying on a bed of nails, riding a hovercraft and shattering glass with sound.

"The 2000-year-old Computer (And Other Achievements of Ancient Science)" -- 7 p.m. Feb. 26 at the Axis Cafe. Columbia University science historian Richard Carrier talks about such Greco-Roman scientific discoveries as the Antikythera mechanism, the oldest known computer, discovered in an ancient shipwreck near Crete.

"PI DAY Puzzle Party" -- 7 p.m. March 14 at the Bazaar Cafe. A boisterous math and logic puzzle competition, hosted by Wes Carroll from Do the Math private tutoring. Compete solo or in a team.
DOWN TO A SCIENCE, SAN FRANCISCO

Informal science cafes at 330 Ritch St., San Francisco, and "science in action" field trips and hikes in the Bay Area. For details, visit http://www.ScienceCafeSF.com. Upcoming talks include:

"Nanotechnology and Medicine" -- Feb. 26. Nanotechnology talk by Dr. Tejal Desai, director of the UC San Francisco Laboratory of Therapeutic Micro and Nanotechnology.

"Air Quality in the Bay Area" -- March 18. Details TBA.

"Science of Solar Power" -- April 15. Details TBA.

"Science in Action" field trips to the Bay Model in Sausalito in February and a solar manufacturing facility in March.

MSRI IN BERKELEY

Coordinated by the Mathematical Sciences Research Institute of Berkeley. For details, visit www.msri.org. Upcoming talks include: