I think I have an idea for a (Homestuck-based) challenge. 

The objective of the challenge will be "Put the bunny back in the box". 

The characters will be put on an island, and have access to a small box. The challenge objective would imply that a bunny used to be in that box. The goal? Explore the island, and find that bunny, and return it to its cube of origin. The catch? This island is full of strange, mostly dangerous wildlife and weird puzzles. :3