Writing Challenge Ideas

Seeing that writing challenges are quite popular among the writers here on WordPress, the following thought occurred to me: why not have a writing challenge about developing a writing challenge?

So, here is what I ask: reblog this post on your blog, and add your three best suggestions for a writing challenge.  From the list we collectively build (and based on “likes” to reblogs) we will offer a series of writing challenges we can all do together.  (Keep the challenge idea SHORT.  One or at most two sentences.)  We will keep deadlines short (maybe a week) so that we can keep the process fresh.