This concept has been rattling around in my brain a bit lately, so I am throwing this out there.
A friend was looking for other October art prompts, and I always have an itch to design characters for fun... I am most certainly not the first to come up with this concept, but whatever, this is just for fun and personal challenge.

Design a character based around the prompt for that block of days.
It can be as simple as a scribbled doodle in a notebook or as complex as you can manage in 3 days, or even a description if you are not inclined toward drawing.
Keep them, sell them, toss them in the corner with all the others, do whatever you want with the designs you create.

In short, this is just a challenge for fun, something that can allow you to step out of your comfort zone (or not! I'm not your life coach).