Seth Godin and crew started this 30 day challenge back at the end of May to commemorate Ralph Waldo Emerson's 208th. birthday. If you signed up, every day you'd get a quote and a question. Well, I kind of missed out on that. But I found out (and it's not listed on their website) that they continued the project. You can still sign up even now and start receiving the emails. Then you just write a response. Supposed to help you think about writing every day and think in general.
Go to their site to get started.