Paul Trapani Keenan Cruz masters the Twirl and Hurl at the Heavy Pedal Cyclecide Bike Rodeo.

The city is spacious today, with the wind tearing down the sidewalks like an unfettered child and the clouds hanging close like an obtrusive aunt with something up her sleeve. Sufficiently bundled, I like days like these -- chilly holiday weekends when half the population has seemingly fled in the night and the other half is locked up snug, and there are no lines in the bagel shop. Treasure Island always has that same ghostly quality, with its flat empty measures of land gone to weed, abandoned barracks and featureless storefronts, and its stoic emblems of once-and-future vainglory rising out of long-undisturbed gravel. It must have been something in its time, all those jeeps zipping around, the rank and file marching and saluting, bugles blaring, buttons on uniforms shimmering; you can almost hear the deep-throated clomp of boots ringing across the pavement. Now I imagine tumbleweeds rolling down the middle of those wide, vacant roads with chilly, gun-barrel-gray water smacking the nearby shore. But tumbleweeds form in brassier climes, so I must content myself with a dog-bitten Nerf football. Which is fine. It's not often you get a chance to see kids horsing around in abandoned lots these days, and it makes me grin watching the two boys as they haul ass over the fallow concrete, making their way through tawny clumps of grass and tossing their small rusted discoveries as far as their arms will allow. Their laughter echoes down the hollow lane, followed by the sharp crack of snaps tossed at each other's feet. It's Fourth of July weekend. Independence Day. Fireworks and Old Glory, free spirits and rebellion, hot dogs and beer. Treasure Island seems a good place to be.

A loose string of cars, trucks, and vans drives past the unattended guard's booth, pulling into a parking lot on the north side of the island, and discharging a motley crew of holiday celebrants with a barbecue. Most of the ladies wear bright hair of man-made hues, borrowed or grown, while many of the fellas sport attention-grabbing facial hair and big silver rings in their ears; nearly all the folks wear slightly misshapen cowboy hats and well-aged leather. From a distance, it's the opening shot of a basement-level cult classic: Post-apocalyptic cowboys ride into a military ghost town. Pan left. But up close it's all business, with hurried talk of "the fuzz," "the site," and "the rodeo." Scouts are sent out on a reconnaissance mission, and the rest of the group is told to sit tight and smoke cigarettes. After a time, the trucks leave the parking lot, snaking toward the far end of the island. The rest of us follow a little ways behind, finding the lead trucks parked in a lot by the icy shoreline. A box truck is opened and a tangle of oddly formed bicycles is wrenched from inside. The crew flies into action, pulling out plywood and lengths of steel and firing up battery-charged electric drills, preparing the field for the Heavy Pedal Cyclecide Bike Rodeo.

A cop rolls in, eyeing the pile of bikes and the flurry of activity, but he doesn't step out of his car. Head rodeo ringmaster Jericho Reese and an unnamed mountain man with a woolly beard and woolier way steps up to the officer. Nothing to see here, officer. Just bicycles. Good, clean, honest self-propelled fun. Open air. Barbecue. Fourth of July. Blah, blah, blah. The officer smiles.

"If anyone complains, you never saw me," he says, pulling out of the parking lot. Mick Jagger's daughter is getting married on the other side of the island, we're informed, so the island bigwigs are well-occupied. The Cyclecide crew jumps in again, and, within a relatively short amount of time, there's a teeter-totter comprised of two bicycles on giant, industrial-sized springs; a galloping cow-bike; a bucking-bull bike; a spinning cycle-contraption, lovingly titled the Twirl and Hurl; a self-powered merry-go-round of pedaled mounts; a game of bike-lane bowling; a large vacillating ramp; a series of miniramps; and a "bike corral" with a tremendous assortment of tall bikes, long bikes, twisty bikes, dune-buggy bikes, baby-buggy bikes, lowrider bikes, highrider bikes, double-framed bikes, triple-trike bikes, teeny-tiny bikes, chariot bikes, lawn-mower bikes, and easy-rider recliner bikes.

The grill is fired up, and a band miraculously appears with guitar, drums, accordion, and amplified microphones. A leather-clad Reese, looking like a squirrelly fighter-pilot from The Adventures of Baron Munchausen, steps up to the microphone and invites everyone to grab a bike.

"These are not works of art meant to be hung on a wall," roars Reese over the wind. "These are bikes that are meant to be ridden. Please, have fun. And if you have kids, please spot them on the Bike- O-Totter."

There are kids in the growing crowd, but if they are anything like "6 3/4"-year-old Keenan Cruz, the adults should be asking for help.

"I've been in more bike crashes than you'd think," says Cruz with a scornful look at my pen as he tears around on the Twirl and Hurl. "Bad ones."

Like Cruz, the rest of the crowd doesn't really need an official invitation to grab weird bikes and careen across the parking lot, swinging foam-padded battle axes at one another with bloodcurdling screams. It seems the most natural course of action, given the circumstances, the setting, and the accordion. A few people take hold of very, very tall bikes and go in search of the mini-golf course rumored to be on the island -- cowboy boots pumping, hats flapping in the wind, and a fading "yee-haw" echoing down the road. Others bowl from atop bicycles while trying to balance their beers and cigarettes, pedal and steer, and avoid braining the scorekeeper. Daytrippers satisfy themselves by pulling loved ones in a buggy or a booster seat. Even Crunch, an elegant Doberman puppy, gets in on the pre-game show, nipping at his human's pant leg as it rises and falls on the pedal of an oxidized long-bike that resembles a hunting praying mantis.

Two new cop cars arrive to survey the scene. Like their earlier cohort, they just pull up close enough to check out all the bikes and try to hide their smirks when two jousting fools wind up in a pile on the pavement. All other voyeurs are summarily chastised for 90-degree knees.

"You gotta get some knee action in before the big joust," suggests the rider of an emerald green grasshopper.

That joust, a title bout between San Francisco champion Don Paul Congo and southland champion Paul "The Carcass" de Valera, is a brutal two-out-of-three, on- concrete affair. The Carcass, having already made mincemeat of the gratefully thick-skulled Jay Brommel, squares off to face Congo.

"Aren't you tired of being called 'San Fransissy'!" incites ringmaster Reese.

Congo beats his breastplate, roars through his leather mask, and waves his lance. The crowd applauds the home team. Sadly, Congo has met his match in the Carcass, and the title goes to Los Angeles. The audience is consoled with some fancy ropework from Ratgirl, who lassos the cow-bike and anyone riding it. Then, it's back to burgers, beer, and music-accompanied bicycle mayhem called the Mosh Pit of Recklessness.

"Happy early Independence Day," shouts a hot number in a flapper dress and a cowboy hat, blowing a noisemaker in my general direction.

Next year the cops want permits, but, for now, happy Independence Day indeed.