I'd like to write off the prompt "behind closed doors" for fun. But I can't seem to find it anywhere! Can somepony help?

3974016
I'm not sure if I understand your question.

That writeoff competition ended a while ago; if you want to write a story now using the prompt, feel free. The story folder is labelled 2014-12 - Behind Closed Doors.

Which reminds me - Roger, we need a folder for this month's writeoff (All In).

3974031

Yeah, I want to write it just for fun. Where would I find the original prompt?

3974035
"Behind Closed Doors" IS the prompt. All the prompts for the write-offs are extremely short.

3974038

Ok!

3974038

But I can't find the prompt "rules" anywhere!

The Rules and the story itself was 2000-8000 words. That's really it, so if you want to play with the prompt for fun, go wild!

Quick recap on how this group's writeoffs normally work:
1) Upcoming writeoff is announced a few days in advance.
2) At the start of the writing period, the prompt (e.g. "Behind Closed Doors") is announced.
3) Now that everyone has the prompt, they have the duration of the writing period (usually either 24 hours or 72 hours) to outline, draft, polish, and submit a fic, as long as it somehow pertains to the prompt (e.g. "Behind Closed Doors") in some sort of obvious way. Fics for the current writeoff are submitted to an external website instead of Fimfic.
4) The external website shows all submitted fics but does not show author names, so no one knows who wrote what. Everyone now has one week to read all of the anonymous entries and vote on their favorites.
5) At the end of the voting period, the authors are revealed, and the winners are announced.
6) Now that the contest is over, people are free to polish the fic further (based on feedback during step #4) and then publish to Fimfic if they want.

Most people only do the active events, but there's nothing stopping you from using an old prompt for fun. In this case, you can just write a fic based around the idea of "Behind Closed Doors", optionally you can self-impose a time limit on how long you have to write it, and then just publish straight to Fimfic.

3974053

Here is also the main website to participate in the next compition.

http://writeoff.me/

I was starting a comment about how I was totally confused when I first found these things too and how we need better introductory documentation and then I realized that the stickied thread named "Questions and Answers" links directly to this complete-looking FAQ on the writeoff site. So I guess me and TheFanficFanPony just failed our spot checks.

PSA: Don't fail your spot checks.

For the record, if you write entries to writeoffs you missed, I believe we said we'll accept them in the proper folder. :O Just make sure you mention the writeoff and the prompt in the description, otherwise someone'll come along and go, "Why is this here? It wasn't in the contest!"