Microsoft co-founder Bill Gates became the latest person to answer the “Ice Bucket Challenge” on Friday, dunking a bucket of ice-cold water and ice cubes over his head in a bid to spread awareness about a neuro-degenerative ailment called amyotrophic lateral sclerosis (ALS), popularly referred to as Lou Gehrig's disease.

Gates, responding to a challenge from Facebook founder Mark Zuckerberg, went about the task of getting soaked in typical geeky fashion. In a video uploaded on YouTube, he is shown planning the entire thing out, so that it is different from what the others have done.

After watching Zuckerberg simply lift the bucket over his head to douse himself in a video and then challenge three people, including Gates, the Microsoft co-founder brings out the drawing board, intending to build a contraption that would help him fulfil the challenge conditions “better”.

The video shows him draw lines as he makes a blueprint—sort of—of the contraption he has in mind. Then we see a stick-and-paper prototype of what he has in mind.

Then, the video shows him put finishing touches to the actual contraption, so that when he finally pulls a rope in the end, the bucket, suspended above him, upends its contents on the world's richest individual.

The Ice Bucket Challenge has become a viral craze in the United States in recent weeks.

It involves celebrities soaking themselves in icy water before challenging other well-known personalities to follow suit.

Zuckerberg, who was nominated for the challenge by New Jersey Governor Chris Christie, laughed as he tipped the ice over himself before daring Microsoft titan Bill Gates, to emulate him.

Gates, on his part, passed on the challenge to SpaceX and Tesla CEO Elon Musk, TV personality Ryan Seacrest and TED curator Chris Anderson.

Television star Jimmy Fallon, singer Justin Timberlake and actor Mickey Rourke have all taken the challenge in recent weeks.

Even Ethel Kennedy, the 86-year-old widow of Robert Kennedy, has taken the challenge—urging US President Barack Obama to follow suit. Obama declined, but made a donation instead.

The rules are simple. The challenge for a person is to record himself on video in continuous footage while being doused in icy water. This has to be done within 24 hours of receiving the challenge.

After the dunking, the individual has the option to donate at least $10 to a charity of his or her choice and call out others with the challenge.

Those who decline the challenge are urged to donate at least $100 to a charity of their choice.

The ALS Foundation, which is the chief benefactor of the donations from the challenge, has said it has collected around $7.6 billion in the two weeks since July 29 to bolster research into Lou Gehrig's disease.