NEW YORK (CNN/Money) - Joe Millionaire? This fall, someone will have a chance to become Joe Billionaire, thanks to the marketers at Pepsi, Warren Buffett, and a nimble-fingered monkey.

The company has announced the May 1 launch of a summertime promotion, "Play for a Billion," in which consumers will compete for large cash prizes, including a potential ultimate payout of $1 billion in September.

There's no guarantee that anyone will win that prize, however. In fact, the chances of doing so are infinitesimally low. Still, the contest represents the latest upping of the ante in an even larger, corporate sweepstakes known as reality TV.

Here's how it will work. The company has printed a sweepstakes entry code on the caps of specially marked bottles of Pepsi, Mountain Dew, and Sierra Mist. Select fountain cups (e.g., at movie theaters) will also have stickers with entry numbers on them.

A billion numbers will be generated, one million of which will be instant winners (a $15 prize). To play for the bigger prize, anyone with a number can enter it on a Web site (not yet launched) or mail it in. Pepsi expects about 15 to 20 percent of all the codes will be redeemed.

From that list of entrants, 1,000 codes will be randomly selected for the big-money competition, a two-hour TV special, to be aired live on the WB Network in September.

Through a somewhat complicated process of elimination, the thousand entrants will be pared down to a list of 10 finalists, who will then compete for a guaranteed $1 million prize.

Once the 10 finalists emerge, they will enter into successive, numbers-based games of chance. Through a process of progressive elimination, the million-dollar winner will be picked.

That winner will hold a multi-digit number. In order for him to become a billionaire, the number must exactly match a number to be drawn at random on live TV.

"An unusually dexterous monkey" will do the picking, says executive producer Matti Leshem. "It's the ultimate slap in the face to evolution: the fate of a billion dollars will be in the hands of a monkey."

In the regurgitative world of reality television, producers are hesitant to reveal the details of any program before it's aired. (Competitors roll out knockoffs faster than you can say, "Joe Millionaire is a Bachelor.")

Nevertheless, the show -- produced by Diplomatic Productions, which was responsible for "Who Wants to Be a Millionaire?" -- is shaping up to be a reality TV spectacular.

Super sweepstakes The biggest individual sweepstakes prizes to date have all been won in pay-to-play lotteries, such as Powerball. Location  Date  Amount  West Virginia  12/25/02  $315 million  Indiana  7/29/98  $296 million  Massachusetts  4/6/99  $197 million  Wisconsin  5/20/99  $195 million  New Jersey  7/16/02  $165 million   Source:  Multi-state Lottery Association

"There's going to be a big-name celebrity host, and plenty of great entertainment," says Leshem.

Marketing experts estimate that Pepsi will spend about $15 million to advertise "Billionaire," roughly the same as it spent on last summer's marketing efforts. There will also be extensive promotional tie-ins with the WB Network and its corporate parent, AOL Time Warner (which also owns CNN/Money).

The game-show angle represents a creative push to build word-of-mouth attention for Pepsi. "This is a bigger idea than our previous marketing," says spokesman Dave DeCecco. "We think it will really drive excitement around the Pepsi brand, as people start talking about the sweepstakes."

No matter how many people ultimately watch the program, though, can any product marketer afford to give away that much cash? After all, as the late Sen. Everett Dirksen once observed, "a billion here, a billion there, and pretty soon you're talking real money."

For help, Pepsi turned to Dallas-based SCA Promotions. The firm provides financial protection called "prize coverage services," a process of insurance and re-insurance that allows marketers to offer oversized prizes without assuming outlandish risk.

"By mitigating risk, we help companies offer a prize that would be beyond a sponsor's ability or desire to pay," says Robert Hamman, SCA president and founder.

"It doesn't take long to call the roll of companies that would be willing to take part in a super-jumbo case like this," says Hamman. The only possible U.S. underwriter: Warren Buffett's Berkshire Hathaway (BRK.A: Research, Estimates).

In return for a seven-figure premium (less than $10 million), Berkshire has assumed the risk of a payout. If the monkey picks the right number, the winner will receive an annuity worth $1 billion, payable over a multi-year period. (As in a lottery, the recipient could instead choose a smaller, one-time payout.)

As noted, that probably won't happen. If it does, though, Pepsi would be thrilled, because the promotional value of a billion-dollar payout would be inestimable. Even better, the money would come from Berkshire Hathaway.

That company, among other things, is the largest shareholder in Coca-Cola (KO: Research, Estimates).