Justin Timberlake, Matt Lauer, Martha Stewart and the Kennedys have all done it.
They've taken the Ice Bucket Challenge that's helped raise $2.3 million for the national ALS Association since July 29.
That's compared with raising $25,000 in donations during the same time period last year, according to an e-mail from Carrie Munk, association spokeswoman.
Here's how it works: Dump a bucket of ice water over your head and nominate someone else to do the same. Ethel Kennedy nominated President Obama to take the challenge. He's passing but still donating the money.
The challenge is all being done to raise awareness of ALS or amyotrophic lateral sclerosis, better known as Lou Gehrig's disease.
The Ice Bucket Challenge has taken off on social media. People have posted photos and videos of themselves on Facebook and Twitter, using #IceBucketChallenge.
The viral challenge started when Pete Frates, a 29-year-old Massachusetts resident diagnosed with ALS, started posting about it on social media, said John Frates, Pete's father.
Frates, a former captain of the Boston College baseball, knew Boston athletes, who accepted the challenge. From there, the local news stations picked it up and soon celebrities and politicians were doing it too, John Frates said.
ALS attacks the nerve cells controlling voluntary muscle movement, yet leaves the person's mental capability intact.
There is no treatment and no cure for ALS. Someone diagnosed with the disease usually has 2-5 years to live, according to the ALS Association.
Frates said his son's story is particularly compelling because the diagnoses rarely affects people under the age of 30. Pete is married and has a baby due next month.
"It cut him down in the prime of his life," Frates said. Pete is now "completely disabled. No use of his extremities."
Pete cannot speak and has a feeding tube because he can no longer swallow. He uses a computer with eye retina software to communicate.
The reach of the Ice Bucket Challenge has exceeded even Pete's expectations, his father said.
"Pete's always been a ball payer, so he always says, 'Go big or go home,'" Frates said. "But even for him, he's blown away."
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