Basically, a person records a video of himself/herself pouring ice cold water on himself/herself. This is after being challenged by someone else. Failure to accept the challenge means you should automatically donate $100 to an Amyotrophic lateral sclerosis (ALS) related charity.
Among the celebs who have posted videos of themselves doing the stunt include: Justin Timberlake, Taylor Swift, Mark Zuckerberg, Bill Gates, Cristiano Ronaldo, Justin Bieber etc.
Peter Nyong’o posted his video on instagram. Here it is.