So like the title says, we want to know what kinds of challenges you, the users, want to see more of. We ask users to give ratings of the challenges after completing them already, but we'd like some more feedback.
In case it's helpful or interesting for anyone, I've made the result of the ratings public, so feel free to take a look: Challenge Statistics. It's worth noting that debugging and timed challenges have a lower number of votes in general due to the fact that the user is usually not viewing the page at the moment they complete the challenge (due to the nature of how these challenges work).
Based on the ratings, it looks like the Beginners challenges are the most popular, though that may just be because they're the first ones users attempt. What kinds of challenges would you like to see more of?
Additionally, someone suggested recently to show the answer for already completed challenges, not only after completion, but always. It's on my todo list.