I'd love some collaborators.
If you want to create your own challenge, just submit it as a pull request. In general, I've tried to make every challenge self-contained in a docker image and restrict user interaction to flask endpoints. If this doesn't fit for your desired format, just let me know.
If you have some pretrained models that you'd like to turn into adversarial challenges, I'd love to help package them.
If you want to playtest or write walkthroughs, please let me know.