If you logged on to weibo over the weekend, chances are your newsfeed was flooded with videos of US celebrities drenching themselves in ice water. It seems everyone is getting in on the fun, from popular singers like Taylor Swift and Justin Timberlake, to high-ranking of tech executives including Bill Gates and Mark Zuckerberg.

It’s a fundraising game called the Ice Bucket Challenge, and it aims to raise awareness for amyotrophic lateral sclerosis (ALS).

The challenge’s premise is straightforward. It involves daring a person to dump a bucket of ice water over their head within 24 hours, or donate money toward fighting ALS. Even if a person completes the challenge, they’re more than welcome to donate money anyhow.

Once a person completes the challenge, they’re supposed to issue the same challenge to several other people, usually three, which is why the challenge has been growing and growing.