If you've been on social media this past week, you might've seen videos of people dumping buckets of ice water on their heads.
By now the trend has swept up the likes of Matt Lauer, Martha Stewart and "The Fault In Our Stars" star Ansel Elgort.
FOX NEWS: "It's the Ice Bucket Challenge — we showed you Elisabeth yesterday. It's to raise awareness for ALS, or Lou Gehrig's disease, and also to raise money!"
ALS is a disease that causes neural deterioration and leads to impaired motor functions, paralysis and ultimately death.
The ALS Association reports more than 5,000 people are diagnosed with the disease in the U.S. each year and as many as 30,000 Americans are living with the disease at any given time.
That answers the question of why people are taking the challenge, but why the challenge consists of dumping ice water over your head is a little unclear.
The challenge originated with Peter Frates, a former collegiate baseball player from Massachusetts who was diagnosed with ALS in 2012 at age 27. (Video via YouTube / Will McAuliffe)
FRATES VIA A LIFE STORY FOUNDATION: "I was one of the worst offenders, not knowing enough about ALS. ... I didn't really know what it did; I didn't know the ramifications."
In an interview with "Today," Frates' father, John Frates, said the family started the challenge a few weeks ago, saying, "When the ice hits you, even the toughest guy becomes a puddle."
A lot of times when a cause goes viral over social media, like Kony 2012 or the #bringbackourgirls campaign, pundits start to question whether they actually do any good. But the Ice Bucket Challenge seems to be making a real difference.
As USA Today reports, since July 29 the challenge has helped to raise $2.3 million for the national ALS Association, compared to just $25,000 during the same period last year.
The trend doesn't seem to be showing signs of slowing down, either, with Justin Timberlake joining the increasingly long list of celebrities to get soaked — and challenges have been issued to both former President Bill Clinton and President Barack Obama, with the latter's representatives saying the president would make a monetary donation instead.
This video contains images from Frank Gaillard / CC BY SA 3.0 and Getty Images.