The new crop of commercials for the annual advertising bacchanal known as the Super Bowl is rife with ads made and designed by amateurs, a sign that the do-ityourself culture in popular entertainment is spilling over into the world of advertising.

There are also plenty of traditional spots, hocking everything from Toyota’s new truck to Revlon’s new women’s hair coloring product. There may even be a marriage proposal and an ad that would be music to the ears of Beatles fans.

All of these commercials are planned because, if the past is any indicator, Super Bowl XLI will attract the largest television audience of the year. In this era of TiVo, advertisers don’t want to miss that rare opportunity of placing an ad during a show people will watch live, en masse, even if they have to pay up to $2.6 million for a 30-second spot.

These advertisers know that many of the expected 90 million Americans tuning in to watch the Chicago Bears take on the Indianapolis Colts will not really care about the outcome of the purely Midwestern matchup. Watching the ads has become as much a part of Super Bowl Sunday as the game itself.

“For the Super Bowl, ad agencies create ads meant to entertain, because that’s what people watch the game for,” the chief creative officer of the Madison Avenue advertising agency Roberts and Tarlow, Andy Langer, told The New York Sun. “A Super Bowl ad needs to be memorable.”

That may be why this year’s offerings include a large number of ads created and designed by amateurs. Doritos, Chevrolet, and even the National Football League invited fans to submit their own concepts for ads, with Doritos even having them produce the ads themselves.

Mr. Langer, who while at the agency Lowe created Johnson & Johnson’s “Having a baby changes everything” campaign, ascribes this to the success of the Web site YouTube and the enormous popularity of viewer-produced content.

While the executives who run Doritos may think that having the public vote online to determine the favorite among five amateurmade commercials is a good way to make a splash, some marketing experts disagree.

“Have the inmates taken over the asylum?” Jack Trout asked of the decision to let amateurs write million-dollar commercials. Mr. Trout, known for his pioneering work in product placement and now head of a Greenwich, Conn., consultancy, Trout and Partners, questions the effectiveness of ads that aim to amuse.

“The purpose of advertising is to sell things, not entertain,” he said, adding that advertisers “panicked” by the technology that allows viewers to skip commercials should focus on dramatizing what differentiates their product. “I think it’s a fad. It’ll wear itself out,” he said of the homemade commercial phenomenon.

Given the popularity of the television show “American Idol” and its gimmick of allowing Americans to vote for the entertainers they like best, it comes as little surprise how integral a part online voting plays in these campaigns.

AOL will again allow viewers to vote for their favorite Super Bowl ad after the game. The company reportedly streamed some 42 million copies of the Super Bowl ads in the week after last year’s game, and it is selling ad space on its site this year.

Some of the more traditional campaigns are seeking to take advantage of Sunday’s huge audience to launch new products. Revlon is airing its first Super Bowl ad, featuring the pop singer Sheryl Crow using a hair-coloring product. This is remarkable given how few women’s products get advertised during the Super Bowl.

Even the pop star set to sing the national anthem, Billy Joel, has a lot to gain from this exposure — he just happens to be releasing his first pop single in 14 years, a ditty called “All My Life,” next Wednesday.

The mainstays will be back, too. Anheuser-Busch has bought five minutes of ad time, making it once again the largest advertiser. On top of its commercial with the stalwart Clydesdale horses, its ads will include a spot with race car driver Dale Earnhardt Jr. and another featuring rapper Jay-Z and former Miami Dolphins coach Don Shula depicted in holographic images.

This year, the Super Bowl advertising orgy may be as notable for ads that may or definitely will not air as for those that do. A man who wants to place an ad in which he proposes to his girlfriend is still seeking sponsors to come up with the fee. (Readers dying to know if he makes it, or who want to find out whether it just a marketing hoax, can follow the saga at mysuperproposal.com.) The animal rights group People for the Ethical Treatment of Animals was turned down by CBS for its humorous ad linking meat eating with erectile dysfunction.

“You want to win the contest to be the most talked about ad at the water cooler on Monday,” Mr. Langer said. That’s possible only if you make it onto the broadcast.