The Ice Bucket Challenge, sometimes called the ALS Ice Bucket Challenge, is an activity involving the dumping of a bucket of ice and water over a person's head, either by another person or self-administered, to promote awareness of the disease amyotrophic lateral sclerosis (ALS, also known as motor neurone disease and in the US as Lou Gehrig's Disease) and encourage donations to research. It went viral on social media during July–August 2014. In the US, many people participated for the ALS Association, and in the UK, many people participated for the Motor Neurone Disease Association, although some individuals opted to donate their money from the Ice Bucket Challenge to other organizations.
The challenge encourages nominated participants to be filmed having a bucket of ice water poured on their heads and then nominating others to do the same. A common stipulation is that nominated participants have 24 hours to comply or forfeit by way of a charitable financial donation.
On August 1, 2015, a group of ALS organizations in the United States, including the ALS Association, Les Turner ALS Foundation, and ALS Therapy Development Institute, re-introduced the Ice Bucket Challenge for 2015 to raise further funds with the intention of establishing it as an annual occurrence. Accordingly, people performed the challenge again in summer 2016.