They're an odd bunch: the hobbled grandparents who fight over a bag of potato chips, a boisterous family that builds super-fast motorcycles and the heavy-set gangster who demands a cream puff.

Twenty years ago, Apple Computer Corp. rocked the advertising world with an iconic ad to introduce a product called the Macintosh. Since then, the Super Bowl has become the undisputed testing ground for the most ambitious and aggressive ideas in the advertising industry. Super Bowl XXXVIII Feb. 1 will be no different.

And why not? Despite a slumping TV season and questions in some corners over the benefits of network advertising, there's no arguing with the staying power of the Super Bowl as one of the most effective ways of reaching tens of millions of attentive viewers all in one shot.

In fact, viewership of the Super Bowl has been on the rise in the past few years, reaching 88.6 million last year, according to Nielsen Media Research, up from 84.3 million in 2001, the last time CBS had the game. The broadcast rotates among ABC, Fox and CBS under a $500 million, eight-year deal with the NFL announced in 1998.

The high demand for Super Bowl spots comes against a background of continued erosion in network TV ratings as advertisers have more choices for reaching viewers.

For CBS, part of the Viacom Inc. media conglomerate, the Super Bowl could prove to be a bonanza. With about a week left to go, nearly 90 percent of the 60 ad spots have been sold, which marketers say is about right for an average year.

"We're in good shape," said Jo Ann Ross, the head of advertising sales for CBS.

With television viewing fractured as it is, advertisers see the Super Bowl as one of the country's few widely shared entertainment experiences and strive to be part of it.

"There is nothing else like the Super Bowl. It's 'water cooler' — it's an event," said Donna Wolfe, chief negotiation officer for national broadcast advertising at the Universal McCann ad agency.

"When you talk about regular prime-time programming, there are more choices every year," Wolfe said. "It's not that people are watching less television; they have more choices."

On the other hand, when nearly 90 million people are glued to their sets and not only watching commercials but critiquing them, it all can have a terrifying effect on marketing executives, who want to make sure their ads are "Super Bowl-worthy."

Viewer polls ranking the ads, such as a popular one done by USA Today, can cause major heartburn for companies betting $2.3 million — the average cost of a 30-second ad this year — that their message will be a hit.

"Nobody wants to wake up in the morning and see themselves at the bottom of the survey," said Jason Maltby, who buys TV ad time on behalf of advertisers for Mindshare, a firm owned by WPP.

For veteran advertisers such as brewing giant Anheuser-Busch Cos., producing top-rate commercials for the big game is business as usual, Maltby said. But for first-timers, "there's a lot of pressure on them to make sure their commercial stands up."

That hasn't deterred Staples Inc., which is buying its first Super Bowl ad this year. It depicts a greedy worker named Randy who parcels out office supplies in exchange for bribes of doughnuts and pastries. A colleague eventually calls his bluff, confronting Randy with a bag of office supplies from Staples and backup from the hulking gangster character Joe Viterelli from "Analyze This." Viterelli's demand to Randy is as menacing as it is unequivocal: "Cream puff."

Staples' marketing chief Shira Goodman said buying a spot made sense, since the company is in the middle of a major campaign to refocus its image on convenience. Staples is changing its slogan from "Yeah, We've Got That" to "That Was Easy."

"The time was right for us," Goodman said. "We had a very important message."

Expedia, the online travel site, also bought its first Super Bowl ad, but the company, like many advertisers, is keeping its contents secret. Spokesman David Dennis would say only that the spot is similar to its current campaign showing how Expedia can help travelers find the right trip.

America Online, the online service owned by Time Warner Inc., is in a wide-ranging $10 million Super Bowl promotion deal that includes three spots, sponsorship of the halftime show, an online poll of the ads and promotions during the NFL post-season.