How about a creat-a-card,design your own deck of cards and then as the prize have it printed.
Why not a genre switch challenge. If you do cards, learn something with coins. If you are a self proclaimed purist, learn something with a gimmick. Do something you normally wouldn't.
Post about what you usually do, then what you want to learn.
Then, after practice, post a video of you performing what you learned.
The one who seems to have done the best job with crossover wins.
It'll force you to look at a different side of magic, with a prize in store if you do a good job.
Here's to becoming a more diverse magician! *clinks drink glass*