The Ice Bucket Challenge went viral about four years ago, and raised $115 million to fight ALS. Now something called the "Lemon Face Challenge" is trying to do the same thing for another good cause . . .
You have to eat a lemon wedge and record yourself reacting to how sour it is. Then you challenge at least one other person to do it.
It's a little easier than dumping a bucket of ice water over your head. But if you don't want to do it, you're supposed to donate to a group called Aubreigh's Army to help fight DIPG.
DIPG is a type of brain cancer that attacks the brain stem. And it tends to affect little kids. (It stands for Diffuse Intrinsic Pontine Glioma.)
An 11-year-old in Alabama named Aubreigh Nicholas was diagnosed last September, and started the challenge by daring Alabama football coach Nick Saban to do it.
He did it last Thursday and posted a video.