Ice Bucket Challenge

"I accept the challenge," said Microsoft founder Bill Gates to the dare to pour a bucket of ice water over his head. He was eager to outdo his challenger, Facebook CEO Mark Zuckerberg (pictured above). Gates welded a contraption together which held a bucket of water at the top. Pulling on a lever, he released the bucket that doused him in freezing water.

Whether CEOs, pop stars, actors and footballers - the videos where they tip a bucket of water over their heads generate millions of clicks - and millions of dollars. This harmless internet fun is for a good cause though: donations are collected to help fund research for the incurable motor neuron disease, amyotrophic lateral sclerosis (ALS).

Trapped in a paralyzed body

Physicist Stephen Hawking, probably the most famous ALS patient, sits in a high-tech wheelchair and communicates through a voice computer controlled by his eyes. ALS destroys nerve cells, leading to muscle paralysis. Estimates suggest some 150,000 people worldwide suffer from the disease. This is relatively few, in comparison to other neurodegenerative diseases such as Alzheimer's or Multiple Sclerosis.

A lack of research triggered the 'Ice Bucket Challenge.' The rules are simple: Once a challenger has been doused in ice water, they have to nominate three more people to do the dare within 24 hours. The whole thing is filmed, the video is posted online and shared on Facebook and Twitter.

World Cup winners get iced

German stars are also getting in on craze. Bundesliga players Mario Götze and Jerome Boateng nominated their national team mates, Lukas Podolski, Mesut Özil and Marco Reus to take part. Former German handball star Stefan Kretzschmar went for the hottest nomination, daring Germany's Chancellor Angela Merkel to take part. Otherwise she would have to donate $100 (75 euros) to the ALS foundation, which supports the fight against the disease.

The online community waited in vain for a video from the garden of the Chancellery - in the end, German comedian Oliver Pocher stepped in for Merkel. Even the White House declined to participate with US President Barack Obama turning down the dare made by Ethel Kennedy, US Senator Robert F. Kennedy's widow.

"The President appreciates Mrs. Kennedy thinking of him for the challenge," the White House announced. "The President [will] be making a donation to an ALS charity this week."

Reluctant role models

Various social media campaigns have come and gone - most borne out of boredom. Comparatively harmless was the 'Planking Challenge.' Challengers lay down, alone or in groups, flat like a board and post pictures of it on the net. Soon after it developed into a test of courage, people looked for the most dangerous places to 'plank.' An Australian fell to his death from a seventh floor balcony as he attempted the stunt.

Just as bad are the various beer challenges - nominees skull half a liter of beer, otherwise they owe their nominator a slab of beer. This gained momentum - hardcore challengers drank in extreme conditions, others took it a step further and drank spirits from the bottle. The campaign claimed several lives.

The 'Fire Challenge' has also proved fatal. Most challengers are young; they douse themselves in lighter fluid, then set themselves alight. The person who burns for the longest time is declared the winner. Again, people have died.