"We clearly need to do something so that our party and the people can make the right decision," Clinton, sounding somber, told reporters in Philadelphia.

"So I have a proposal. Today, I am challenging Senator Obama to a bowl-off. A bowling night, right here in Pennsylvania. Winner take all. I'll even spot (concede) him two frames," she said to guffaws from the press.

"It's time for his campaign to get out of the gutter and allow all of the pins to be counted. And I'm prepared to play this game all the way to the 10th frame," Clinton added.

"So let's strike a deal, and go bowling for delegates. We don't have a moment to spare, because it's already April Fool's Day."

On Saturday, a grinning Obama played to the crowd in a bowling alley in gritty Altoona, several times sending balls wobbling into the gutter instead of crashing into pins at the end of his lane.

The excursion, a new twist on "gutter politics," "didn't go so well," Obama said. "There was an eight-year-old who was giving me tips," he said, before assuring voters that his economic plan was far better than his bowling.

Biofuels made from food crops such as corn, sugar, soybeans and oil palm burn cleaner than fossil fuels, but experts say high demand is sending ripples through the world economy, and could be doing the environment more harm than good.

Rudy Gosal, a 36-year-old courier who queued with hundreds of others in Indonesia's capital in March to buy government-subsidised cooking oil, is one of millions feeling the pinch of the push towards biofuels.

After the latest rise earlier this year, the cost of cooking oil in Jakarta jumped a massive 70 percent, to around 12,000 rupiah (1.31 dollars) a litre……

……A study published in the journal Science in February found it would take around 86 years for biodiesel made from palm oil grown on cleared tropical lowland forest to repay the "carbon debt" generated from clearing the land.

For biodiesel from cleared peatlands, the study found, the debt would take more than 840 years to repay.

"Certainly the carbon debt from converting peatlands is far and away larger than in any of the other ecosystems we considered," said Jason Hill, an economist at the University of Minnesota and study co-author.

But Indonesia appears intent on running up that debt. Already at least 10 million of its 22.5 million hectares (55.6 million acres) of peatland have been cleared, according to the Centre for International Forestry Research, and the clearing shows no sign of slowing.

Camera crews discovered a colony of Adélie penguins while filming on King George Island, some 750 miles south of the Falkland Islands.

The programme is being presented by ex-Monty Python star Terry Jones, who said: "We'd been watching the penguins and filming them for days, without a hint of what was to come.

"But then the weather took a turn for the worse. It was quite amazing. Rather than getting together in a huddle to protect themselves from the cold, they did something quite unexpected, that no other penguins can do."

Petty Officer 2nd Class Michael A. Monsoor fought dozens of battles in the streets of Ramadi, shouldering his MK48 machine gun without complaint in the 130-degree heat of Iraq's violent Anbar province.

In May 2006, only a month into his first deployment to Iraq, the 25-year-old Navy SEAL from Garden Grove, Calif., ran under fire into a street to drag to safety a wounded comrade who was shot in the leg, earning a Silver Star for his courage.

On Sept. 29, 2006, another act of valor would cost Monsoor his life — and save the lives of three comrades. For that act, he will posthumously be awarded a Medal of Honor on April 8, the White House said yesterday.

Monsoor "distinguished himself through conspicuous gallantry and intrepidity at the risk of his life," said an official summary of action. He is the first sailor and the third service member overall to receive a Medal of Honor for actions in the war in Iraq.