Somehow, you do not expect your snowboard instructor to be on time. Ours, 20 minutes late, has just pulled into the muddy parking lot of Lake Tahoe's Ski Homewood in a huge 1968 Lincoln Continental. Beside him is a can of starting fluid, for coaxing cold engines to life; in the backseat are piled six snowboards, for the participants in this weekend's clinic. He is wearing a baseball cap, retro-seventies Arnet sunglasses, and a tiny whiskery "soul patch" under his bottom lip. The sleeves of his flannel shirt are unbuttoned and there appears to be a tattoo on his right arm. As he climbs out of the car, a big grin on his goofy face, I can see he is almost as tall as the Lincoln is long.

He is Rob Wells, or Mr. Personality, as one ski area employee calls him, and we are here for his two-day adults-only snowboard clinic. It's a program meant to entice older people—who incidentally have more money—into what's seen as a young person's sport. Indeed, Wells used to offer a senior citizen discount to students over 35. The assumption is that older people are eager to try snowboarding but might feel out of place in a class full of people who look like Rob Wells. This seems the perfect compromise: we've got Rob Wells, but he's surrounded by the more conventional rest of us. Besides me there are Meg, Carolyn, and Lisa, all in their thirties, Jackie, who is 64 and a locally renowned windsurfer and mountain biker, and, believe it or not, Rob's father, Bob, 47, who has driven in from Sacramento and has never tried this before either.

Rob Wells's native tongue is California surfer-speak, but he gives a convincing try at standard English as he outlines what's in store. Today we'll be "getting our feet wet," he says (this turns out to be literally true), tomorrow "feeling our way around"; if we persevere on our own after that, we'll "just be sweet and cruisin'." Skiing ability is said to speed your progress, but is by no means required.

Rob takes us through putting on our boots and attaching a foot to the board's front binding. Next comes learning how to ambulate on the flats, which is done by standing on the front foot, pigeon-toed in its binding, and pushing off with the back foot. (The back foot stays out of its binding until you're ready to go downhill.)

Soon the fun begins: we push our boards a few steps up a bunny slope, point them toward the bottom, and glide down. It's hard to stay steady. "The board is like a wet bar of soap," Rob says. "If you lean on one side, it'll slip out in the other direction." But it also has edges for gripping—a "toe edge" and a "heel edge"—and will act like a big fat ski once you get the hang of it.

We try a little leaning to the left, a little leaning to the right, a little wiggling both ways, and there's a glimpse of the future, a small presentiment of what it might be like to actually GET IT.

Sooner than I'd expected, Rob proposes that we all ride the Poma lift up the practice hill. There are murmurs of doubt—many hands and behinds are already damp from falls, and it seems unlikely the situation will improve on steeper terrain. But Rob points out that the practice hill is in the sun. We clubfoot it over there.

In the lift line I ask Rob's dad if he was an investor in SnoWave Snowbordz, the shop Rob founded three years ago, and he looks at me as if I'm crazy. "No, it was Rob's own thing. He found the investors; he put it all together by himself." Did he have any training, I wonder—any business courses? "No," says Bob, like someone who lost an argument long ago. "Rob has no professional training. In fact, he has no training of any kind."

But somehow this charismatic autodidact gets us to the top. A sideslipping lesson follows, and before we realize it most of us are able to make a turn in one direction and come to a stop. "Pretend you're opening a door," Rob says, demonstrating how to initiate a turn with the upper body. His long arm traces a slow semicircle from his chest, his gangly body changes direction, and the snowboard follows suit; it's surprisingly graceful. "Be tall, be tall!" he yells out as I find myself slowing to a stop after one turn. "Easy for you to say," I shout back, before realizing that straightening up has taken me off my edge and back into the fall line, ready for another turn. Then, by "opening the door" the other way, I discover I've linked two turns: I'm snowboarding!

Seconds later I'm flat on my back and my sunglasses are full of snow. Jackie, Meg, Carolyn, and Bob are all similarly positioned. Lisa slides by me, if not exactly tall then at least medium-size and looking at ease. Filled with envy, I lift myself up to try again . . .

The snowboarding phenomenon is now perhaps five years old, and heading from a youthful fringe into the mainstream. Various sorts of mono-skis have made sporadic appearances on the slopes for years, of course, but snowboarding is different: it is rooted not in skiing but in skateboarding and surfing. As such, it enjoys a huge constituency of teenagers. From 5 to 10 percent of lift tickets in the United States are now sold to snowboarders, and the number is rapidly growing.

Snowboarding is not just another way to get down the mountain. "Riders" have created a bona fide snowboarding subculture with its own language and fashion. The lingo borrows from skateboarding (an "ollie" is a lifting of the board into the air), surfing ("shred" is a rather passe term for riding well), even mountain climbing (a "grommet" is a fledgling snowboarder). Rider fashion is an offshoot of the inner-city gangsta look: overlong baggy jeans, outsize T-shirts and flannel shirts left untucked, baseball caps worn backward. Then there's the all-important attitude, marked by a love of tricks and maneuvers and a disdain for skiers, whom snowboarders view as staid and materialistic. Snowboarders, on the other hand, are the bohemian vanguard. Even if they hail from the same suburbs.

For their part, many skiers aren't thrilled about snowboarding. Snowboards make a lot of noise, and those on them have a reputation for being impolite and even dangerous: learning to snowboard takes less time than learning to ski, so young upstart riders with little experience in ski area etiquette are quickly on top of the mountain. A good many may be out of control, but then again, more than a few kids on skis are reckless, too; snowboarders are just singled out more easily.

We make our first chairlift foray later that afternoon. A wonderful expectancy comes over me: the terrain below is familiar but will now have to be negotiated in a completely different way. There is nothing like learning a new sport for making the old world new.

Everyone is now able to turn in both directions more or less reliably, and Rob has decided weare ready for a gentle intermediate run. This may be overly optimistic. Having a comforting view of the parking lot replaced by this lofty perspective over blue Lake Tahoe sets knees aquiver, and several of us take our worst spills of the day. At this point most of the class adjourn to the hot tubs at their lodges. But the rest of us, giddy with our progress, decide to ride one last run.

Like many last runs, this one is probably not a good idea. The sun is setting and the shaded slope is icing up. Every one of us slides much of the way down on something other than our snowboards. I lose my cap in a fall and don't even realize it; Meg simultaneously veers off into a bramble patch. As we struggle to our feet we hear a roar like a jet engine and look up the hill to see two young snowboarders coming down full bore, tattooed, bare-chested, and, we think, reckless. To our amazement, the long-haired one stops on a dime next to Meg and helps her out of the bushes. "I think those boots are a little loose," he observes. "You'll get better control if you tighten them up." And then they're off. We gaze after them like gawky anthropologists who've just discovered that the barbarian tribesmen are FRIENDLY.

By the time we reach the bottom of the lift, we are snow-covered and glassy-eyed. The lift operator turns to stare at us and smiles a little.

"It's our first day!" Meg explains.

"No! REALLY?"

Morning brings sore inner thighs, wrists (you fall on them a lot), knees, and even necks. "I'm gonna hate life today," says Caroline, incisively.