With all the publicity NaNoWriMo (National Novel Writing Month) has gotten on line it is easy to forget that November is actually National Writing Month (ALL forms of writing in fact) with the goal of getting people to write something everyday.
Here are some sites to motivate your writing:
You can join in the NaNoWriMo challenge http://www.kcet.org/socal/checklist/event/national-write-a-novel-in-30-days-month.html
If you are interested in a more academic approach check out http://chronicle.com/blogs/profhacker/november-is-academic-writing-month/43608
Or if you are more interested in a non-academic but still Non-Fiction subject try http://writenonfictioninnovember.com/
I personally will be trying the 30 day Blogging challenge, every day in November I will post to one of my blogs, for ideas and info check out http://www.blogher.com/blogher-topics/blogging-social-media/nablopomo
As well as Novels, works of non fiction, academic pieces there is so much you can write about, do not let your lack of interest in long form work or your doubt in your ability control you.
You can Journal both on line and in a physical journal, http://journalingprompts.com/
This might be a good time to try Art journaling with both art and words, http://artjournaling.ning.com/
If you want write poetry (try many different forms) http://www.creative-writing-now.com/how-to-write-poetry.html
Or scripts, (if you want try writing a script to your favorite series) http://www.screenwriting.info/
Perhaps even get some nice paper and write letters to family and friends (try actually mailing them) http://www.wrightslaw.com/advoc/articles/DRAFT_Letters.html
In the long run all that matters is you write, write anything but use this challenge to develop the habit and hopefully dont let it go