How about a design contest with weekly topics? The participants create images, illustrations, comics etc. about a specific topic (for example global warming, delicious breakfast, outer space, ... ).
How the images will be created is free choice. It can be hand drawn, or handmade collage, or with software and computer programs.
And the most important condition: original content.
I think it would be a great opportunity to connect many many designers, creators and makers on this platform. ;)