Can you imagine explaining the contemporary garment known as a T-shirt to George Washington? Picture the guy dressed in layers of scratchy underwear, breeches, dress shirt, heavy jacket, tights, boots and a hat like a complicated folded napkin. And there’s you saying, “Two hundred-plus years after your death, the T-shirt is basically all anyone will be wearing from the waist up; it’s a thin cotton garment the weight of a dish towel, with short sleeves and often inscribed with some kind of funny picture or slogan.” Cut to the father of our country exclaiming, “You, my fellow citizen, are befooled.”

Today the T-shirt is the ubiquitous item of clothing in vacation settings and everywhere else; even the once-uptight business world is succumbing. Here’s a forecast: By the year 2010, Casual Fridays will spill over into all the other days of the week, with perhaps Dress Up Mondays marking the only anomaly. Here on the Vineyard, T-shirt trendsetters have taken the art form to new levels, starting with . . .

The Black Dog: You’ll spot this little doodle of a black lab on T-shirts spanning the globe from Hong Kong to Fairbanks. No one is quite certain how this graphic set the bar so high for T-shirt sales in America, but the Black Dog Tavern in Vineyard Haven, sometime back in the Seventies, printed up a batch of tees that replaced the Lacoste alligator as an indicator of cool. It could just as easily have been a brioche design from The Scottish Bakehouse or a purple petunia from Heather Gardens to make the fashion statement of “I’ve been to Martha’s Vineyard” but, no, the pooch would not perform the downward facing dog for any rival.

C’est La Vie: This innovative boutique on Circuit avenue has, for the past 11 summers, provided tees promoting Oak Bluffs as a state of mind more than a seaside resort. Past (and still going strong) tees proclaim “Sisters on the Bluffs” depicting three leggy, skinny black ladies, “The Inkwell” for the town’s hiply named beach, “Oaks Bluff” as an in-joke for the initiated about the supremely uninitiated, and “On Vineyard Time” for those of us who wish to make it clear we won’t be rushed. The latest star tee features a celluloid strip of human faces, identical yet differently colored. The back reads: “Underneath the Skin We Are All Brothers And Sisters.” Owners Roger and Jennifer Schilling (with the encouragement of one-and-a-half-year-old baby Roger) are developing a Barack Obama tee for August, but Republican visitors need not feel slighted: The store sells G.O.P. cookies.

Beetlebung’s Inkblot Lobster : Rorschach tests can elicit all kinds of reactions, and this psych-exam lobster on a T-shirt is bound to suggest dinner to one person, an irate traffic cop to another, and a midnight freak-out on Squibnocket Beach to still another. The new, chic dry goods shop on Main street in Vineyard Haven is a spin-off of the Beetlebung coffee house down the block on Beach Road. Owners John and Debbie Molinari have been going wild all winter with 20 — count ’em — new T-shirt designs including an irradiated lobster (must be from Sengekontacket Pond). The inkblot lobster tee is the must-have for Vineyard cognoscenti.

Jellyfish: In its second sizzling summer, this graffiti art-splotched apparel shop on Circuit ave has so much buzz, Gen Y’ers drop in thinking it’s a bar but, finding no appletinis, hang out anyway. Last summer, owners Garrett Box and Hawken Morrison kept the cash register ca-chinging with tees promoting the defunct but dearly beloved Islander ferry, and grade school mascots like the Oak Bluffs Blazers and the Tisbury Tigers. One of the 2007 Jellyfish shirts read “Edgartown Face With An Oak Bluffs Booty.” This year the guys have rolled out a new line, with their favorite tee revealing “I Love Gay Head.” Yes, it’s a sweet sentiment — a bit of nostalgia for the old Aquinnah name — but it also carries a double entendre, and those who get it are the ones buying the shirt.

Menemsha Blues: In the manner of the Black Dog, the Menemsha Blues brand, with apparel stores in (duh) Menemsha, Edgartown and Vineyard Haven, has staked it all on a single logo, but it’s a keeper. The big slate-blue, beautifully etched fish, emblazoned on tees and sweatshirts, is polished, even a little stuffed looking. This is the catch you’d hang on your wall rather than marinade in tarragon-infused oil and toss on the grill. But for any Vineyard idolater who has handled a rod and reeled in one of these feisty critters, this is the T-shirt de rigueur.

Sanctuary: You stroll into this ultra-popular shop on Circuit, and in five seconds you’re feeling as Satori-cized as the Paramahamsa Yogananda (whose autobiography just happens to reside on Sanctuary shelves). It’s the soft, non Air-Wicky fragrance, the celestial music, and the heavenly ceiling painted with sky and clouds. Owners Rita and Frank Imbimbo might even have a button they can push to roll back this same ceiling should one of their customers get an extra dose of bliss and begin to levitate. Now Sanctuary debuts its first T-shirt line with messages such as “mind/body/spirit”, “breathe” and “namaste.” The T-shirt pictured on these pages features a scroll of eclectic religious symbols bearing the inscription, “many names, many forms, all one.” Wear any one of these in the summer when 50 lollygagging tourists inhabit every three square feet of sidewalk, and you’ll feel as if you’ve been meditating on top of a quiet knoll on Chappy.

The Lazy Frog: Fun-loving owners Jake and Sarah Gifford, for their new store on South Water street in Edgartown, have designed a frog in the shape of the Island, its legs splayed out and its bulgy eyes thrusting up into West and East Chops. The T-shirt celebrates this goofy creature, and the brand’s mission statement promotes “leisure, laziness and fun.” What is it about frogs that makes us happy? A frog this lazy and downright dopey-looking is bound to cheer up the gloomiest of the store’s target audience, “tadpoles, froglets and croakers.”

Trader Jack’s: Who would have thought that death’s head mannequins could be so engaging? The Army/Navy and pirates emporium on Circuit avenue has long showcased T-shirts for the bivouacking and plank-walking crowd. Actually the entire store is a shrine to boys’ (of whatever age) testosterone-infused instincts, offering martial arts gizmos, noisemakers, gag gifts like rubber lobster droppings and seagull poop, and tees reeking of pirate charm or soldier whimsy. This season’s T-shirt biggie depicts an armed marine and reads “Defend Oak Bluffs.” Well, you never know when a ferocious preppie army to the east could bear down on this festive town. Other favorite tees: “It’s All About The Booty,” “Saucy Wench” and, beneath a skull and crossbones, “The beatings will continue until morale improves.”

Aboveground Records: This (literally) rockin’ music store at the Triangle in Edgartown sells CDs, tapes, music videos, vinyl records and, who knows?, maybe even your Aunt Bea’s 45-lp demo produced in the buck-a-record booth in Coney Island circa 1964. The store also hosts live music performances with artists such as Willy Mason, Maynard Silva, Jemima James and Kahoots. When a few years back, owner Michael Barnes decided to issue a T-shirt — an asterisk-ed white letter “a” against a black background — he had no idea he’d be launching the textile equivalent of the pet rock. In 2005 the New York Times featured the shirt on the cover of its Sunday magazine. The Times contended that, while off Islanders might believe Black Dog gear is the thing to buy, Vineyarders plunked down their T-shirt dollars for the Aboveground Records model. It’s been flying off the shelves ever since. Mr. Barnes says he prints only two batches a year, so customers are frequently mad at him for running out of their preferred color. “What do they want? I never thought I’d be in the clothing business. I sell music!”

Sharky’s Cantina: This overnight success of a Mexican food joint on Circuit avenue, a boisterous, jumping affair, with a new, second location in Edgartown, should it happen to incarnate in Manhattan, would require velvet cords and beefy bouncers to admit crowds only as capacity allowed. A success of this magnitude needs a T-shirt, and it needs a retail space to house it, this one located steps across the covered arcade running alongside the restaurant. The logo from the sign was transferred to the shirt: a grinning Great White shark in a sombrero, lofting a margarita. The other hot-ticket tee shows a small green citrus fruit below the inscription Lime Disease. Any wearer of the Sharky’s tee is making a life style point: I’m fun, I’m cool, and I’ve stayed home a total of two nights out of the past year, both times because I had a flat tire and couldn’t find the car jack.

Island Grown Initiative: This grass roots nonprofit organization, nurturing 28 Island farms and countless backyard growers, encourages all of us to buy and devour Vineyard produce. For years now Cronig’s Market has been selling the group’s T-shirt to the green scene’s in-crowd. It’s a noble endeavor, and it’s a beauty, in hip colors from tie-dye to preppy pink-and-green. The tees seem too attractive for gardening wear, but you’ll want to flash it anywhere, even at work on all but Dress Up Mondays.