Well, for these particular challenges, we're all on a Discord server (https://discord.gg/createwithclint), and these are semi-regular community challenges. There are also smaller weekly competitions, but these are the big community collabs:

Parallel Dimensions (11/2020) - https://www.youtube.com/watch?v=EdCvwmebWN0

Alternate Realities (06/2021) - https://www.youtube.com/watch?v=iKBs9l8jS6Q

Infinite Journeys (03/2022) - https://www.youtube.com/watch?v=JXrWPLNp9tw

Moving Mediations (09/2022) - https://www.youtube.com/watch?v=8b5k0M8wTBg

Pwnisher has a bunch of subscribers, making a 5s clip isn't outrageously time consuming, and it's a fun competition!

He's done a few of these community challenges:

https://youtu.be/iKBs9l8jS6Q https://youtu.be/JXrWPLNp9tw https://youtu.be/EdCvwmebWN0 https://youtu.be/8b5k0M8wTBg

Wow. I don't think I've ever felt less imaginative.