It seems an unlikely pair — the trendy SpongeBob SquarePants teaming up with the aging Etch A Sketch.

Ohio Art Co. is banking that replacing Etch A Sketch's familiar red rectangle case with Nickelodeon's most popular cartoon characters will make the iconic baby boomer toy more appealing to kids and young mothers.

Other toy shelf staples also have gotten makeovers.

Monopoly is out with a new version that replaces the Atlantic City Boardwalk with Times Square. And who can forget when Barbie ditched her longtime beau Ken just two years ago.

Traditional toys have been losing ground to electronics in recent years — sales fell 4 percent to $21.3 billion last year, according to the market research firm NPD Group Inc. For the makers of classic toys, creating a new look is one way to compete against video games and the holiday season's "must have" toys.

"Our challenge is to continue to make Etch a Sketch exciting for the next generation of kids," said Martin Killgallon, marketing director for Bryan-based Ohio Art. "One way to do that is with licensing."

Two new versions that will start appearing in stores this month feature SpongeBob and Dora the Explorer, two of the most popular preschool characters on TV today. The new editions include screen overlays with puzzles and mazes.

By teaming with Nickelodeon, Ohio Art hopes to reach a younger age group at a time when children are giving up toys at earlier ages.

The deal also sets up opportunities to cross-promote its products with the popular television network. "They're the hottest licenses going today," Killgallon said.

It's not the first time Etch a Sketch has shaken up its look. The company experimented with pink and lime-green versions and heart-shaped ones. The classic version is still available, too. Ohio Art won't release sales figures but says they have been steady in recent years.

More than 100 million Etch A Sketches have been sold worldwide since it was invented in 1960. The drawing toy, which operates with two knobs to create pictures, is by far Ohio Art's best-known product. The company makes a variety of learning-based toys.

Hasbro Inc., the nation's second-largest toy maker behind Mattel Inc., reported in October that sales are up 7 percent this year for its classic board games, which include Clue, Monopoly and Trivial Pursuit — all of which have multiple versions. Monopoly alone has about 200 different editions.

There's a fine line, though, when it comes to updating a classic. Lego Group found out in 2003 when it tried expanding beyond its plastic building blocks and began developing action figures, clothing and a television show. The Billund, Denmark-based company fell into a financial crisis, losing $237 million that year.

"The key lesson we learned the hard way is that classic brands need to maintain what makes them loved," said Michael McNally, Lego's brand relations director.

The company no longer makes action figures and outsources the clothing production. The TV show also has been dropped, returning Lego's focus to its colorful plastic bricks. Now sales are back where they were five years ago, McNally said.

Giving a classic toy a new look without altering it too much is a smart move, said Jonathan Samet, publisher of The Toy Book, a trade publication.

He said even though some of best-known traditional toys — such as steel erector sets — have all but disappeared from stores, they do have a strong name recognition with grandparents and moms.

"They just keep buying them," he said. "The Slinky doesn't go away. Etch A Sketch never goes away. Monopoly never goes away. Classic toys just keep coming back."

Childhood development expert Stevanne Auerbach, who's known as Dr. Toy, said classic toys are the backbone of play. Board games teach children to take turns and strategic thinking.

"Kids can have as much fun with these toys as we did when we were kids," she said. "When they have these variations, it just extends the kind of play."