Since we seem to be announcing our challenges ahead of time, I figured I'd go ahead and announce my idea for descendant lang challenge!
The challenge will be to derive a new conlang descended from one of a list of conlangs presented (we can vote on which langs have sufficient quality, completion and detail to be used. A language must receive two votes other than the nominator's in order to be proposed- but if the nominator is the owner of the lang, you need three votes. Nevertheless, please consider nominating other languages instead of your own.) You must of course provide sound and grammatical changes as well as semantic shifts from the ancestor. Also, include some borrowings from the languages you did not derive your own lang from (I'd say at least 25 words from each language, this may change depending on how many languages end up in the final list.) Once the submission date (whenever that ends up being) is reached, the victors will be announced by group vote.
The challenge will start whenever Kauf's germanic-lang and AK's collablang challenges end.
Please post suggestions for the ancestor languages in the comments, and also vote for proposals people have already made.
Edit: Since a large amount of high-quality complete languages on this wiki appear to be a posteriori, I'm changing the rules to allow them as ancestor langs. However, re-gramaticalized and re-lexified languages will not be accepted as ancestors- they must be unique and original, as that is the point of this competition.
Edit: Since concern has been expressed that people can start early due to this being announced ahead of time, there is a secret rule you must obey that will not be released till launch.