Remember that red-bordered magic screen with the two little white knobs that used to be your favorite travel toy? Now you've bought your 4-year-old an Etch A Sketch and, admit it, you're still trying to draw more than two squiggly lines in that sea of aluminum powder and plastic beads.

Well, get ready for a shock, baby boomers. Etch A Sketch just turned 30.

It's amazing that this little gray screen that erases itself with a shake remains even remotely popular in today's high-tech world of whirring and talking battery toys. The simple 7-by-9-inch plastic drawing board with a mechanical stylus has managed to become an American classic.

"It's right up there with Barbie, Slinky and Hula-Hoops," said William Killgallon, chairman of the board at the Ohio Art Co., which manufactures the toy. "It's part of our history."

Now the Capital Children's Museum is celebrating its survival with an exhibit of Etch A Sketch freeze frames by five artists who have developed this as a medium. On display are 16 fine-lined sketches of animals and clowns, a castle and a baseball glove as well as a delicate rendering of a young boy fishing off a pier. The designs have been preserved by gluing the powder and beads to a permanent backing, said an Ohio Art spokesman.

The show also includes a display of how an Etch A Sketch works.

Anyone who ever tried to draw a circle only to produce an indecipherable parallelogram will appreciate the dexterity required to create the clean renderings produced by these Etch A Sketch experts.

Mark Allison is the artist behind some of the exhibit's most inventive works, including an intricate sketch of a snorkeler swimming with stingrays and another of two lively saxophone players in a bar.

Allison started fiddling with an Etch A Sketch when he was 3, growing up in Byran, Ohio, home of Ohio Art toys. Now a junior high school teacher in Bedford, Mich., and a freelance illustrator, Allison says it's a hobby he can't shake.

"It's become second nature to me," said Allison, who creates most of his pieces in about an hour. "I sit in an easy chair and unwind by turning the knobs." Ohio Art Co. pays him $33 a sketch and employs him as a demonstrator at toy shows.

The original Etch A Sketch was the brainchild of French toy designer Arthur Grandgean, who created "L'Ecran Magique" in his garage in the mid-1950s. He and his partner tried to peddle it in New York, where nobody, including Ohio Art, gave it a second glance. In 1959, they pitched it with an elaborate lighted display at the Nuremberg Toy Fair in West Germany, and Ohio Art jumped. The price: an unheard-of $25,000.

It was a solid investment. Fifty-two million Etch A Sketches have been sold worldwide since then, and 8,000 new ones slide down the assembly line every day.

"We knew it was going to be a hit when everyone on the flight back was taking turns playing with it," said Killgallon, who was then Ohio Art's sales manager.

By 1976, an Etch A Sketch Club had been formed. Today it boasts 20,000 members from 25 countries and links enthusiasts through a newsletter, a pen-pal exchange and drawing competitions. Membership is $2 for three years and includes a cartoon patch and hat.

"We call it mom's favorite toy," said Ohio Art Public Relations Director Pat Grandy. "It's self-contained, quiet and involves imagination. In the industry we call that good play value."

Granted, sales slumped a bit in the years when mega-hits like the Cabbage Patch dolls hit the market, Grandy said. But lately Etch A Sketches have become the new party toy for baby boomers and college students. "I get calls from adults who love it," said Grandy. "Recently a creative director from MTV called asking for a four-foot Etch A Sketch for his lobby."

Matt Bunn, 28, editor of Arms Control Today and an Etch A Sketch Club member, admits the toy holds a particular fascination for his generation. "You would be surprised how often at a party people will pick it up and play with it," he said. "And I like the idea of total erasability."

A certain Etch A Sketch clumsiness is common to most adult amateurs with little time for serious practicing.

But luckily Etch A Sketch has modernized a bit and made the experience easier for noncreative types. Ohio Art now puts out "fun screens," acetate accessories that fit over the screen and map out games, mazes and dot-to-dot patterns to follow.

The Etch A Sketch for the 1990s, dubbed Animator 2000, is not nearly as popular as the original, but allows you to "create moving cartoons" by storing pictures in sequence on 12 different screens to make a computerized picture book.

The appeal of the Etch A Sketch has been partly economic. Its original 1960 price was $2.99. Today it's $10. But it's also a great time-waster, as addictive as the Rubik's cube and as universal as a yo-yo.

Before television became the babysitter, Etch A Sketch kept children mesmerized with a different screen. It has carved a niche in our collective childhood memory that refuses to be erased with a shake.

The show continues through July 14 and ends with a birthday party that day. There is also a table of Etch A Sketches for youngsters to play with.