Boston - Good news for your Viagra-using hamster: On his next trip to Europe he'll bounce back from jet lag faster than his unmedicated friends.

The researchers who revealed that bizarre fact earned one of 10 Ig Nobel prizes awarded Thursday night for quirky, funny and sometimes legitimate scientific achievements, from the mathematics of wrinkled sheets to U.S. military efforts to make a "gay bomb.''

The recipients of the annual award handed out by the Annals of Improbable Research magazine were honored at Harvard University's Sanders Theater.

A team at Quilmes National University in Buenos Aires, Argentina, came up with the jet-lag study, which found that hamsters given the anti-impotence drug needed 50 percent less time to recover from a six-hour time zone change. They didn't fly rodents to Paris, incidentally - they just turned the lights off and on at different times.

Odd as it might be, that research might have implications for millions of humans. The same cannot be said for another winning report, "Sword Swallowing and its Side Effects,'' published in the British Medical Journal last year.

It was the world's first comprehensive study of sword swallowing injuries, said co-author Dan Meyer of Antioch, Tenn., one of only a few dozen active sword swallowers in the world. Not surprisingly, throat abrasions, perforated esophagi and punctured blood vessels were the most common injuries.

"Most sword swallowing injuries happen either after another smaller injury when the throat is tender and swollen, or while doing something out of the ordinary, like swallowing multiple swords,'' said Meyer, who went a month without solid food after doing the latter in 2005.

The Ig Nobel for nutrition went to a concept that sounds like a restaurant marketing ploy: a bottomless bowl of soup.

Cornell University professor Brian Wansink used bowls rigged with tubes that slowly and imperceptibly refilled them with creamy tomato soup to see if test subjects ate more than they would with a regular bowl.

"We found that people eating from the refillable soup bowls ended up eating 73 percent more soup, but they never rated themselves as any more full,'' said Wansink, a professor of consumer behavior and applied economics. "They thought 'How can I be full when the bowl has so much left in it?' "

His conclusion: "We as Americans judge satiety with our eyes, not with our stomachs.''

Harvard professor of applied mathematics L. Mahadevan and professor Enrique Cerda Villablanca of Universidad de Santiago in Chile won for their studies on a problem that has vexed anyone who ever made up a bed: wrinkled sheets.

The wrinkle patterns seen on sheets are replicated in nature on human and animal skin, in science and in technology.

"We showed that you can understand all of them using a very simple formula,'' Mahadevan said. His research, he says, shows that "there's no reason good science can't be fun.''

Other winners include a Dutch researcher who conducted a census of all the creepy-crawlies that share our beds, and a man who patented a Batman-like device that drops a net over bank robbers.

This year's planned Ig Nobel program included a two-minute speech by keynote speaker Doug Zongker consisting only of the word "chicken,'' and a mini-opera entitled "Chicken versus Egg,'' performed by professional mother-daughter opera singers Gail Kilkelly and Maggie McNeil.

Most winners are more than happy to accept their awards from real Nobel Laureates at the typically rowdy ceremony, including seven of the 10 winners this year. But there are still a few sticks-in-the-mud, magazine editor Marc Abrahams said.

The U.S. Air Force won the Ig Nobel Peace Prize this year for its proposal to develop a "gay bomb'' - a chemical weapon that would make enemy soldiers want to make love with each other, not war with the enemy.

Abrahams talked to a number of retired and active Air Force personnel to try and get someone to accept the prize in person on behalf of the military. None would.

"Who in their right mind would turn something like this down?'' Wansink said.