''I get this all the time,'' said Mr. Hooper, who prefers to be known as Hoop, as he stood at the door of his garage. ''I'm like my own museum.''

Behind him was a peculiar sculpture that looked something like his own head, oversized front teeth, scraggly red beard and all. It was about the size of a small car. In fact, underneath the felt and fake fur was a small car, a rare 1961 British Trojan that opened from the front like a refrigerator.

That wasn't all the Impala was there to gawk at. In the driveway was the Can-vertible, a 1972 Fiat covered with crushed cans, and a 1941 Packard hearse wrapped in black and tan fur with giant fingerprints. At the curb was a van with two front ends; one side, layered with glued-on timepieces, was labeled ''Millennium Machine.''

Hoop's fleet, unique as it is, is part of a phenomenon that has been taking shape and rolling onto the roadways of America for the last 20 years. The art car -- its roots tangled in everything from the proselytizing chariots of traveling preachers to the billboard-style signs on delivery trucks to the tie-dyed school buses of hippiedom -- seems to have been invented in dozens of places simultaneously.

''A lot of people who do this don't know about anyone else when they start,'' Hoop said. He certainly didn't in the early 1980's, when he banged a dent out of his 1958 Isetta, covered it in fake fur and hit the New York club scene.

One result is the extreme diversity of the cars. If the Fords, Saturns, Chevies and Hondas sparkling in dealers' lots are so many streamlined Rockettes in a perfect kick line, art cars form more of a riotous mosh pit.

A Volkswagen Beetle in California is mosaicked in marbles. A 1970 Oldsmobile 98 in Montana is covered with mirrors. A draftsman in Hackensack, N.J., painstakingly painted his 1985 Buick Skyhawk a fine red plaid, and a musician in nearby Montclair drives a 1991 Toyota pickup that has an earth goddess on the rear door. Kelly Lyles, a Seattle artist, not only drives an art car -- a Subaru station wagon done up like a leopard -- but she also paints formal portraits of them. In New York City, 53 television sets stud Dan Lohaus's 1992 Toyota pickup and several hundred remote controls plaster its hood.

And Phillip Treuvey, a professional spackler who lives near Wayne, N.J., has been adding layers of images onto his Volkswagen bus for the last nine years, using found objects -- fly swatters, key chains, flowers -- as stencils.

Getting a convincing explanation for these efforts is not easy. Tim McNally, who has spent more than 300 hours on his Plaidmobile, said he began after reading a letter from a friend enthusing about her new car, which was a special blue color.

''I thought it would be fun to write back that my car is plaid,'' he said.

Perhaps the clearest explanation comes from Harrod Blank, a Berkeley, Calif., artist, who has written books and made films about the phenomenon of the art car. ''It's a personal totem, a shrine on wheels,'' said Mr. Blank. ''Something you put love and time into, to transform it from something that's mere transportation to something that's special. Because you spend so much time in it, you want it to be you. It's like taking refuge in your room. Same kind of energy, just a bit more extreme.''

Some art cars are subtle. A man in Houston glued a beer can, upright, onto the roof of his car and drives around delightedly eliciting yells from the helpful: ''Hey, you got a beer on your car!''

''It's like the Wright brothers,'' said Gene Pool -- his legal name -- a New Yorker once famous for growing fields of living grass on automobiles. ''There are all these people trying to fly at the same time.''

Now that such vehicles -- once the provenance of individual oddballs, determined artists and Deadheads -- show up regularly in the rearview mirrors of sedate sedans and rugged suburban sport utility vehicles, there is an explosion of events focused on them.

There are established art-car festivals and parades in Houston; San Francisco; Minneapolis; Baltimore (where there are actually two); Key West, Fla.; Decatur, Ill., and Lawrence, Kan., to name just a few. Some attract a handful of odd cars, others draw hundreds of art-car pilgrims from across the country.

Mr. Blank has even found he can eke out part of his living by acting as an agent for artists willing to hire their cars out for advertising or movie work. (For instance, he has arranged for art cars to appear in a Hewlett-Packard advertisement for a printer and on a French billboard for an insurance company.) ''That's the only way I can survive,'' he said.

Mr. Pool said the trend is evidence of the strength of the nation's individualism. ''The people who do this get sick of being just another car,'' he said.

But it also testifies to the relatively open laws of the American road. Japanese and German visitors ooh and ah over the cars, then ask if they are legal. And the trend is also a product of the economy of the automobile market, where new cars regularly cost $20,000, while battered but serviceable and insurable junkers trade hands for no more than a few hundred dollars.

And it's not just about getting attention. ''It's not, 'Look at me!' '' Hoop said. ''It's like, 'How do you like this?' ''

Tim McNally, the painter of the Plaidmobile, said that his car spreads a little cheer. ''Especially on the road,'' he said, ''where a lot of people need cheering up.''

Philo Northrup, an artist who, with Mr. Blank, founded the Artcar Fest in San Francisco, which held its third gathering last month, said that art cars address a gap in American culture: ''The institutions for art and religion are not meeting the needs that are out there. I think you've got a population that has as much spiritual and creative energy as any other, but the churches, synagogues and museums are all talking to each other -- they're not talking to us.''

Still, even the art world no longer considers art cars only as outsider art or folk art. On Saturday, the Triton Museum of Art in Santa Clara, Calif., will open a show dedicated to art cars made by Californians. The Cincinnati Contemporary Arts Center is exhibiting the ''Inside-Out Car'' -- a '79 Volkswagen Rabbit that Dan Devine, a New York artist, cut apart, turned inside out, and rewelded and reupholstered. (If more proof of art-world recognition is needed, consider this: There is no Blue Book listing for a Rabbit that old. Mr. Devine's price tag is about $40,000.)

In a most human sign that the art-car phenomenon has really arrived, it is already showing signs of factionalization. The granddaddy of art-car events, the Orange Show Foundation Art Car Weekend, held in Houston every spring for the last 12 years, attracts creators from around the country. Perhaps a third of the scores of cars are made specifically for the parade and are stored or disassembled in between.

In contrast, the San Francisco festival focuses on cars that Mr. Blank refers to proudly as daily drivers.

But some art-car creators think even that kind of festival strays too far from normal driving, ruining the point as they see it -- to bring a surprising dash of art into everyday life. As Hoop put it, ''I have my own art-car parade every time I go to the grocery.''

Parade Routes

ART-CAR festivals and parades occur around the country at all times of the year. Many are listed on the Art Cars in Cyberspace Web site at www.artcars.com. In testament to the grass-roots nature of the phenomenon, most of the festivals take place in smaller cities; none are scheduled for urban strongholds like New York, Chicago or Washington.

Nearby suburban areas, though, seem to be fertile art-car soil. In the New York area, for example, Jan Loe, a musician and artist who lives in Montclair, N.J., expects to put together her fourth art-car parade next summer. (For information, telephone (973) 746-1412.) Past parades have drawn a dozen or so of the region's eclectic cars, including the Plaidmobile, by Tim McNally, of Hackensack, N.J.

The oldest and largest of the nation's festivals is the Orange Show Foundation's weekend event in Houston. It has been held for 12 years and usually includes more than 200 hot rods, low riders, classic cars and what the organizers call ''artist-built rolling contraptions.'' Next year, the festival, officially the Pennzoil Art Car Weekend, is scheduled to run April 14 and 15. For information, send E-mail messages to orange@insync.net or telephone (713) 926-6368.

A Baltimore artist, Conrad Jay Bladey, is trying to organize a cyberfestival in the next month. Mr. Bladey has invited art-car owners, via an E-mail list-serve, to register their location on Nov. 6 at a Web site (www.geocities .com/MotorCity/Garage/1329 /artcarshow.html). Would-be spectators can visit the site to see whether any art cars are in their vicinity.
ANDREA KANNAPELL