On one of the websites I manage I'd like to run a series of public, open-ended creative writing contests where users submit short entries, and then other users up- or down-vote the submissions. (For example, the contest might be to provide a punchline to a joke, or to provide a caption for a cartoon.) I'd like to know if there's any software I can use or adapt for this purpose.
My requirements for the software are as follows:
- It must be free software.
- It must work with a GNU/Linux server running Apache.
- It should handle all the user authentication (allowing users to create a dedicated account, or to sign in using a third-party identity provider like Google or Facebook).
- Ordinary users should be allowed to submit entries to an existing contest, and to up-/downvote and comment on others' submissions, but the ability to create new contests should be reserved for me (or to special "moderator" accounts).
- Each contest should have its own page showing the contest rules and all its submissions, and the site's landing page should list all the active contests and preferably also their top-voted submission.
- I should be able to customize the site's appearance via CSS.
- I should be able to block any accounts used for spamming or other disruptive purposes, and to delete their contributions.
Basically I am looking for something very similar to Stack Exchange, except that only moderators can post new "questions" (contests). I had a brief look at some of the Stack Exchange clones but couldn't confirm if any can restrict ordinary users from posting new "questions". I could pick one which is otherwise good and try to modify it to suit my purposes, but perhaps someone here knows of one which already does what I want off the shelf.