On the occasion of the host's 40th birthday and the imminent obliteration of his brick split-level house near Vienna, on the occasion that it's the dead of August and that sometimes the green, clover-lawn suburbs of Northern Virginia cry out for subversion, Nutstock III convened Friday evening in a beige-carpeted living room on Five Oaks Road.

It was to be the Nutstock to end all Nutstocks, the most ambitious of the quasi-underground gatherings thus far: 40 bands in 40 hours, spanning three days.

About 8 p.m., the people, most in their late thirties, began arriving with their battered black and silver guitar cases, with their Peavy amps, their Korgs, their Moogs and their Casio synthesizers.

"Hey, Sam, what's going on?" Jeff Bagato, a Nutstock founder, said to the guy walking in.

"Life," said Sam Serafy, 41, who works part time at the Library of Congress and was playing later in a band called Picture is Dead. "Love."

Most of the furniture was cleared from the living room; there were tortilla chips in the kitchen and tents set up in the long back yard for those who wanted to camp out by the sound barrier wall. Someone made a Nutstock banner out of construction paper.

Host Peter Geddes, a clean-shaven man who works in finance, had written the tentative schedule on a whiteboard in the foyer: Atrocity Exhibition, From Quagmire, Jakuta and Carl, Kahoutek, Ricketts 330 and Spacelab, among other bands, would play 20-minute sets starting at 9 p.m.

"Tonight's more ambient lounge," Bagato said, explaining the mood of the lineup. "Tomorrow is barbecue, grilling and rock and novelty acts like a Lindsay Buckingham tribute band. Sunday's an unplugged pancake jam."

Nutstock is not an advertised event; it is not a festival, per se. It is rather an assembly, a fluid network of sorts that began unofficially at Virginia Tech, when Geddes, Bagato and others shared a house, threw parties and formed Alzo Boszormenyi and the Acid Achievers, among other bands. One of the members, David Craig, now a tech guy with Fairfax County public schools, began recording the band and created a label he called Nut Music.

At different points after college, two or three of the original group lived together again in the rental house on Five Oaks Road. They decorated it with a plaid chair, a blue flowered couch and thrift-store paintings of an elderly man sipping red wine, of nude women cavorting around a lake, of a black dragon swooping over a castle. The neighbors were tolerant. It was a fine place for parties.

As people grew up, got married and moved away, the idea of Nutstock was really about getting them back together to play music and commune. The first was in 1998 and featured eight bands; the second one, in 2003, had 18. They were both at the house on Five Oaks Road.

Geddes is the last of the original group left in the house, which is part of a block of ranches and ramblers that a developer wants to demolish to make way for luxury condominiums and office buildings. No one really wanted to talk about it Friday, but Nutstock III was the end of an era.

"It hasn't sunk in yet, but this is all going to be gone," Craig said. "Everything is changing. It's like growing up."

About 9 p.m., the house was dark and full of a few dozen people who frequent such places as the Galaxy Hut in Clarendon, sipping wine or Milwaukee's Best or drinks out of blue tumblers. In the step-down living room, where a stage had been set up under the swooping dragon, Craig clicked on a red light and a yellow one. Geddes went to the front.

"Okay, we're going to start out with Mike," he said. "He's going to play the bulba tarang and some guitar."

"Thanks," said Mike Tamburo, who drove from Pittsburgh to play. "Happy birthday. This is called, 'When You Leave Me Don't Leave Your Bones in My Back Yard.' "

And so, Nutstock III began beyond the beige parking garages and smoked glass of the Vienna Metro station.

With the 40th birthday being celebrated, with the prospect of the house being demolished, with summer and so many other things ending, the night had an undercurrent of abandon. People spilled wine freely and smashed tortilla chips on the carpet. Serafy discussed how he'd given up television. Tony Boies was saying he'd brought both his belly dancing and white swan costumes for his set. Craig wondered aloud whether anyone realized what went on behind closed suburban doors.

About 11 p.m., a man called Jakuta in a too-big tuxedo grabbed the microphone and, managing to evoke both David Bowie (in his Heroes phase) and Pee Wee Herman, began belting out, "I had a friend named Ken. . . ! And I told him not to worry about the end!"

With 29 bands to go, Nutstock III went on yesterday in the hot back yard on Five Oaks Road. It is to end about 3 p.m. today.

The band Alzo Boszormenyi and the Acid Achievers, with singer Gregg Gibson, 41, David Craig, 41, left, and Peter Geddes, joined in the party for Geddes's 40th birthday.Swan Man, played by Tony Boies of Ladysmith, Va., performs his theatrics with the Butter Kings during Nutstock III in Vienna.