Two of my online content sites are currently running contests: "Summer Sizzles" (write five articles about summer and get a chance at $101) on Suite101 and a local content contest on Associated Content.
These contests are great for writers for a couple of reasons:
1. They motivate you to write a lot, because hey, you might win something!
2. They give you a prompt to get you started brainstorming.
These are both big factors in my writing for these sites. The pay is low, so it's hard to be motivated to write for them, but I know that if I could just get a big library on them, I could have a very decent stream of residual income.
For the latter, I often struggle with coming up with ideas. Having just the smallest prompt, like "summer", at least sets me in a specific direction. I've already posted four articles to Suite101 for this contest, and two are doing quite well by my standards. In fact, two were Twittered (or is it Tweeted?) by people I don't even know with huge followings! I had my biggest day ever there yesterday. I've submitted two articles to AC so far for their local content drive and they have not been processed yet.
There are many, many writing contests out there for both fiction and non-fiction. Winning one is not only good for your ego and gets you prizes (sometimes cash), but it's good for your resume, too. Plus, they get you writing, which is what is hard for many of us.
My challenge to you, dear reader, is to find a contest and enter it. A couple of places to find them are at Accentuate Writers Forum and the Writer's Market. Enter, then post here so I and others can cheer you on!