I don't see one of these yet, so here's the question for the proposals for the June 2016 Community Challenge! (I skipped May, as there wasn't enough time to get a good pool of suggestions.)

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It's time to choose a [tag:community-challenge] for June 2016.

* Post your challenge as an answer to this question. Feel free to resubmit non-winning ideas from previous months.
* Vote for those answers which interest you.
* At the end-of-day on Wednesday, September 30th, the top-voted post will become the next challenge.

Once the challenge topic is decided, post your solution as a [question on the main site][2] and tag it with [tag:community-challenge]. The challenge runs throughout October (but nothing stops you from posting an entry later on).

  [2]: http://codereview.stackexchange.com/questions/ask