MasterCard, for instance, has learned all too well that in the last-minute rush, things don't always work out as planned.

The credit-card concern was all set with a brash new rock-music spot in its "Priceless" campaign for Wednesday night's Grammys, eager to reach an estimated 27 million music-loving viewers. But at the last minute, it pulled the commercial because of glitches.

In the commercial-from Interpublic Group's McCann-Erickson, the agency that created the successful "Priceless" campaign in 1997-a dad takes his young boy shopping for a first guitar. Dad strolls through the store with his son, and they look at various items as a voice-over ticks off the cost of each: "Your first amp: $200. Your first strap: $30. Your first guitar: $450."

Slash, once lead guitarist for the rock group Guns N' Roses, plays the role of a store shopper.

Then the boy picks up a slick new red guitar. "Mind if I try it?" he asks the guy behind the desk. The boy strums a few chords, then shocks his father when he smashes it to bits before falling to his knees with rock-star flair. "Rock and roll: Priceless," the voice-over says.

The ad was all set to go, but MasterCard pulled it earlier this week, just a few days before the ceremony. Mr Elisa Romm, a vice-president of brand building in MasterCard's advertising group, says the ad was pulled because of "technical issues," which she declined to specify. "It was just one of those things," she says. "We came up with the idea in a week and a half."

The episode says much about the lengths to which advertisers are willing to go to make the most of their marketing dollars in a cluttered and competitive environment. Despite the economic slowdown and a softening ad market, big television events such as the Grammy Awards still command high prices - and attract a relatively specific audience. Advertisers paid $500,000 on average for 30 seconds of air time on Wednesday night's show.

Often it is the agency's idea to go for a bigger splash, as was the case with the MasterCard ad. McCann-Erickson's creative team approached the credit-card firm with the idea of trying to tailor the ad to the Grammys. Ms Romm of MasterCard says they felt the approach would be a "good way to take advantage of the media buy" - or the amount MasterCard spent on the air time alone.

MasterCard also missed out in trying for a similar rush job with last fall's "Subway Series" baseball championship. McCann-Erickson quickly threw together an ad featuring a father and son disagreeing over which of the rival New York teams was more worthy of winning the World Series. The ad was supposed to run during the games, but was never finished because of the walkout by commercial actors in the Screen Actors Guild.

A spokeswoman for McCann-Erickson says the agency's ambitious plans for MasterCard "consistently" work out, and points to successes such as the 1998 ads featuring clips of sluggers Mark McGwire of the St. Louis Cardinals and Sammy Sosa of the Chicago Cubs hitting home runs during their grab for the record. (New balls cost $9 apiece, but a record-breaking 62nd homer is "priceless.")

Faced with the high cost of broadcasting commercials on widely watched shows, it is no surprise advertisers and their agencies will increasingly try to get the biggest bang for the buck. The Grammys are regarded as a key vehicle for reaching the young and hip, and this year, the show attracted such advertisers as discount retailer Target, French cosmetics giant L'Oreal, General Motors and FedEx.

While most ran general commercials promoting their brands, MasterCard and Heineken tried to strike a chord with the rock-and-roll audience. New video technology should have made the whole process easier, because shooting and editing a TV commercial takes less time than ever.

Heineken aired three new ads, from Interpublic's Lowe Lintas & Partners, New York, humorously pretending the Dutch beer was the source of some of the most famous moments in rock history. In "Birth of a Sign," for instance, a guy puts up two fingers to request "two Heinekens, please," but the crowd interprets his fingers as a peace sign and mistakes the word "please" for "peace." It declares, "July 16, 1969 ...A peace sign is born."

Mr Steve Davis, senior vice-president of marketing for Heineken USA, says Heineken initiated the effort. While he concedes that creating the three Grammy ads involved spending an "inordinate amount of money," he contends the investment ultimately will pay off because Heineken will rebroadcast the ads on music cable stations.

One of the side benefits of having an ad pegged to a marquee event is the public-relations bonanza that surrounds the show. Both Heineken and MasterCard hired PR agencies to talk up their Grammy ads. Mr Davis of Heineken says he was thrilled to hear one radio announcer Thursday morning saying that the best thing about the Grammy show was the Heineken ads.

The Wall Street Journal