Running since August 2010 to the present day (with the exception of a hiatus from March 2019 to November 2020) the Custom Content Challenge (or ccc from here on in) is a mechanism for generating new custom content on a regular basis. During each month creators are encouraged to create new material that conforms to a theme that was chosen (by a poll) held throughout the previous month. One thing to note is that it is not a contest. Also submissions do not have to be new models/artwork. For the ccc there is a wider range of the type of things that can be submitted. As long as what is submitted is applicable to the theme, then scripts, sounds, prefabs, etc. are acceptable. Over the years a number of different people have administered this and I currently fill this role as well as continuing to maintain and update a catalogue of all the completed and posted challenges.
For anyone who finds this interesting, here are some links. Please not you will need to be logged in to vote in the poll and may need to be logged in on the vault to view the various threads pointed to (not sure on this). With the catalogue on the other hand, you should be able to download it without being logged in.
Info on the ccc - Custom Content Challenge 2020 - Rules, Guidelines, etc
The current challenge - Custom Content Challenge: March 2021 :Celestial Courts
Poll for next month's challenge - Custom Content Challenge - April 2021 Poll
Where to add your own suggestions for future challenges - Custom Content Challenge 2020 - Theme Suggestions
Every item in every completed challenge to date - CCC Catalogue
Feel free to join in, all are welcome. Any questions just ask, either here or on the vault.