Scientists who suggested rollercoasters could be used to remove kidney stones are among those to be recognised with a coveted Ig Nobel prize.
The awards, held at Harvard University and organised by US magazine Annals of Improbable Research, celebrate unusual, funny but practical scientific work.
The 28th annual ceremony featured the traditional audience-led "paper plane air raid", while real Nobel Laureates were on hand to present the prizes.
Lengthy acceptance speeches were kept short by an eight-year-old girl, who repeated "please stop, I'm bored" after the 60-second time limit.
The prize for medicine was awarded to US researchers for their research into the use of rollercoasters to hasten the passage of kidney stones.
Professor David Wartinger, of Michigan State University, began looking into the area when one of his patients reported that riding on the Big Thunder Mountain ride at Disney World, Florida, had dislodged his kidney stones.
He built a model of a patient's renal system and tested it on rides to prove the theory.
Prof Wartinger told BBC Radio 4's Today program: "Anybody who's trying to generate benefit from our research should be looking for a rollercoaster, which doesn't have to be fast, but you want a rollercoaster that is quick and rough with a lot of up-and-down and side-to-side motion.
"In fact, the really fast coasters that go 100mph and drop hundreds of feet don't really work very well.
"I can't tell you about a general consensus, but I can tell you that for the last decade that we've been aware of this research, we've recommended it for our patients with great success.
"It literally rattles the stone loose."
Dr James Cole, an archaeology lecturer from the University of Brighton, was also recognised, taking home the nutrition prize for quantifying the calorific value of the human body.
After finding other animals provided much greater calorie return, he questioned the idea that human ancestors hunted and consumed members of their own species for strictly nutritional reasons.
"It is possible that some of our ancestors may have eaten members of their own species out of necessity - but it is more likely perhaps to think of the cannibalism act within a social framework rather than a nutritional one," he said.
Dr Cole said he was "honoured" to have his research recognised with an Ig Nobel, adding: "Human cannibalism is a subject that continues to hold a morbid fascination within modern societies.
"In particular, identifying the motivations for human cannibalism remains a contentious issue."
Some of the other winners of this year's awards:
- Researchers who showed wine experts can reliably identify, by smell, the presence of a single fly in a glass of wine were awarded the Biology Prize.
- A Japanese doctor who devised a "self-colonoscopy", which he has demonstrated, won the Medical Education Prize.
- The Economics Prize went to researchers who investigated the effectiveness of employees using Voodoo dolls to retaliate against their bosses.
