Every sixth Saturday or so, dozens of young software developers flock to a small mansion somewhere in Silicon Valley to share technical tips, collaborate on the coding of pet projects, and knock back a few beers while debating the data-models underlying popular start-ups like Facebook and Twitter.

This informal gathering that’s open to the public flows from 2 p.m. to 2 a.m. with free alcohol, energy drinks and innovative ideas. It’s a tech party known as SuperHappyDevHouse, and it’s lured rank-and-file employees of Google, Oracle and still-nameless entrepreneurial endeavors.

It’s this robust swapping of ideas and sharing tricks-of-the-trade across company lines that has given Silicon Valley an innovative edge since the ’70s.

SuperHappyDevHouse has codified that collaborative culture for a new generation of inventors.

DevHouse organizers say they’re trying to “resurrect the spirit of the Homebrew Computer Club,” the legendary ’70s garage gathering of hobbyists Steve Jobs, Steve Wozniak and other founders of computer companies.

Today’s reincarnation, which has been attracting throngs of techies by word of mouth for two years, bills itself as “a party for hackers and thinkers.” It’s a haven for passionate programmers who modify software with creative and sometimes kooky code, as opposed to crackers who break into computer systems.

This 12-hour programming party was the brainchild of now 21-year-old Web developer Jeff Lindsay, who by passed college because he was eager to tackle real-world tech problems rather than sit in classrooms solving problem sets.

While Silicon Valley is cluttered with tech clubs, DevHouse is unique in that attendees churn out technical projects rather than just swap business cards.

Its most successful creation has been PBwiki, an online template for creating Wikipedia-type collaboration Web sites. It received $2 million from Mohr Davidow Ventures in February.

Lindsay said Microsoft offered to host the party at its Mountain View campus, but he turned it down: working in walled-off cubicles would ruin the fun, collaborative atmosphere.

But DevHouse did recently accept a food fund from Mohr Davidow Ventures that covers the $500 tab each party racks up buying beer, Red Bull and snacks to fuel the programmers through the night.

The next party, No. 18, is scheduled for this Saturday in Hillsborough. Expect to see more than five men for every woman. Most are in their 20s and 30s, although a teenage girl has shown up as well as a man with a full head of gray hair.

Hackers hailing from as far as as Dublin, Ireland, plunk their laptops down at DevHouse when they’re in town on vacations or business trips. Some of the regulars relocated here from places like Pittsburgh, Penn., and Lexington, Ky.

“I moved down here because of stuff like this,” said Matt Rubens, a 25-year-old software engineer who worked at Amazon.com and then established a start-up in Seattle. He ditched that in April for Silicon Valley’s scene.

DevHouse has been mimicked in Boston, Mass., Zurich, Switzerland; and Cologne, Germany. Each city hosted its first party in the past six months, but none has offered an encore.

Lindsay and DevHouse co-founder David Weekly are helping programmers elsewhere in the world plan their own open-house hacker parties.

“Silicon Valley is the progenitor of this culture,” Weekly, 28, said as the most recent weekend coding party wrapped up at 1:59 a.m.

A party tour

The last SuperHappyDevHouse, also known as SHDH, drew about 95 people who swung by for various stages of the 12-hour event. Here’s how the party played out on May 5:

2:15 p.m., study hall: Sixteen programmers quietly clack on their laptops while sitting on plush couches that have been pushed against the family room walls so there’s more floor space where later arrivals can sit.

The studious air makes you want to whisper.

A few guys get up to graze the spread covering the kitchen counter: burritos wrapped in corn or flour tortillas, chile verde with pulled pork that’s been simmering for eight hours, and chocolate-chip bundt cakes laced with Godiva liquor.

Barbara Harrison, whose 25-year-old live-in son, Tom, is hosting this SHDH, has been in the kitchen cooking since 4 a.m. And she’s still at it, checking on the casserole and whipping up Rice Krispie treats.

The 58-year-old mother already warned neighbors surrounding their one-acre Los Gatos property that the coding party would go on until twilight. But these guests rarely get drunk or rowdy.

“People stake out a spot and do their little nerdy thing,” she says.

3:28 p.m., syncing up : Three laptop-toting strangers sitting around a table on the sun deck strike up a conversation about quiblz.com, a social-networking polling start-up that is in test mode.

“How are you planning on monetizing it?” asks Sven Strohband, a 33-year-old partner at Mohr Davidow Ventures. The SHDH newbie, who stayed past midnight, came to code an application to manage the venture capital firm’s deal flow but spent almost as much time discussing other attendees’ projects.

Adam Thorsen, a 28-year-old co-founder of the polling start-up, tosses out his ideas and gives a quick tour of the Web site.

“Pretty cool,” chimes in developer Khang Tran. Then Tran offers a demo of his start-up’s social-networking photo site, which is in alpha testing. “I want to get some feedback. Do you mind if I show you guys?”

They scoot closer.

4:37 p.m., tech toys: Usually the Legos are a big hit with this crowd of Internet construction workers. But those go untouched this time. Perhaps because partiers are busting out cool tech toys.

All of a sudden, Martin Bogomolni, who is starting a company making electric cars, zips through the kitchen on the latest model Segway. A dozen programmers leap up to take snapshots with their cameras and phones. Some immediately upload their images to Flickr.com, boasting to the world what a riot they’re having. And perhaps enticing more people to swing by.

5:03 p.m., scouting talent: Not all the attendees are software wonks. Lori Guidos isn’t, so she’s dropping in to find one. The executive director of www.disabledcommunity.org wanders the party looking for a whiz at drupal – a free content management framework – who can help her build a database.

Guidos wants pro-bono work. But lots of developers have snagged paid gigs at SHDH.

Jesse Andrews, a 28-year-old research fellow at a Palo Alto-based incubator of Internet initiatives, says by talking shop with techies here, “you can know if they’re competent really quickly. I already told a couple people today, `Hey, if you’re interested, come into CommerceNet. We’re looking for prototype engineers.’ “

6:59 p.m., more tortillas : Serial entrepreneur Joel Harrison returns home after logging nine hours at the office. While en route, his son had sent him to the grocery store to buy 35 more flour tortillas.

Soon after the 59-year-old eases into a chair, engineers half his age excitedly chat with him about what they’re working on. Some don’t realize they’re swapping stories with a man who co-founded hard-disk drive maker Quantum in 1980. Or that they’re pursuing pet projects, which one day might make them millionaires, in the custom-designed house built with the riches Harrison reaped from that company.

Harrison, now on his seventh start-up, tries to pass as just another techie interested in hearing “fresh ideas.”

“I came home tired,” Harrison says, “but this has invigorated me.”

9:11 p.m., lightning lectures: A white king-size bed sheet hangs over the living room window as a makeshift projector screen for the night’s six-minute technical talks. More than 50 people cram onto the couches and carpet, lean against the walls, and strain to hear from the hallway during the 1 1/2 hours of programming presentations.

“Don’t promote your company,” warns moderator Joe(uml)l Franusic, a 24-year-old network technician in San Luis Obispo. “We want cool hacker tips.”

He shows how to create “the poor man’s VPN,” which can come in handy for WiFi coffee-shop customers who “don’t want people like me watching your chats.”

The presenters are pulled from the podium after precisely six minutes, even if they aren’t done explaining the technology. Sometimes questions arise from the audience. Applause always erupts.

11 p.m., the hot tub: Seven or so partiers unwind in the outdoor pool and hot tub, giving their brains a break from the buzz. After an hour or so, they towel off.

“Longer than that, and I risk my fingers over-pruning,” wisecracks 23-year-old electrical engineer Mike Lundy, “and that would make it hard to type.”

12:41 a.m., hard-core hacking: All 10 chairs in the staid dining room are occupied by techies who are concentrating. Larry Halff, 36, is coding a Web site on which programmers can publish their work so it’s available for others to mash up. Chris Messina, 26, is debating with Twitter’s lead developer about the finer points of adding microformats to the popular service that delivers instant updates on what people are up to.

In the family room, the Musik.funky Internet radio stream from Germany is pulsing loud enough that collaborators need to raise their voices a bit and lean in. Weekly, who founded PBwiki.com as a result of the first SHDH, is writing a Windows drop-box application that instantly posts Microsoft Word documents online. His start-up was prepared to shell out a couple hundred bucks for a programmer in Ukraine to spend the next two weeks writing that. But Weekly has finished the job in five hours – and for free.

2:05 a.m., coffee to go: Barbara Harrison turns off the music and announces it’s time to clean up. She offers coffee that the remaining 35 late-nighters can drink now or take in to-go cups.

As the remaining attendees pull the furniture back into place and pack up the 18 power strips scattered throughout the house, 30-year-old Nathan Schmidt alludes to the data tool he wrote that night as he marvels, “It occurred to me that Facebook’s 60 kilohertz MemCache request is probably primarily driven by the lack of this data structure.”

Five other geeks keep gabbing as they inch toward the front door. “How are you going to allow your restricted code to access a socket?” one asks.

After 75 minutes of tidying up, the Harrisons are ready for bed. But others don’t want to call it quits. Six wide-eyed hackers – including SHDH co-founder Lindsay – hop in their cars so they can continue discussing action scripts, Twitter adapters and theoretical Web services at Denny’s.