What should be our theme for the #AtoZChallenge this year?

April is A to Z month. We've participated the past two years and plan on doing so this year. For smaller blogs and even medium size ones it's a great traffic booster and a way to discover and meet fellow bloggers.
What is Blogging from A to Z? For the answer, check out this post.
The first year I asked for guest posts from our fans, each post about an aspect of writing. For example, the first post of the 2012 A to Z challenge on this site was A is for Adverbs and Adjectives #AtoZChallenge.
The next year, 2013, I asked you to recommend a fellow indie writer. The first post that year was A is for Anneli Purchase aka @anneli33, recom'd by @darlenejones47 #atozchallenge.
I don't have a theme in mind for this year, so the first thing I need is an idea. How should we organize this year's challenge? As in the previous two years, I want the material to come from you.
What should we focus on in April?