It's called the TrashTag Challenge, and it encourages people to clean up litter.
Despite the requirements of some viral challenges, this one is pretty easy to get behind. All you do is go out to an area with litter, clean it up, and take photos of what it looked like before and after.
Once you've snapped the photos, post them online using the hashtag #TrashTag.
Some Houstonians are sharing their photos on Reddit, with one user saying they cleaned up Little White Oak Bayou near Wrightwood Street.
If the phrase #TrashTag sounds familiar, it could be because the brand UCO first came up with the #TrashTag Project in 2015 to encourage people to pick up after themselves and in the great outdoors.
But whether you've heard about it years ago or you're just getting hip to it, now seems like a good time to get involved!