I love this blog.
Virginia DeBolt, a regular contributor to BlogHer, maintains First 50, a blog of writing prompts. The premise is simple: she poses the prompt, and those who want to write 50 words on the topic--fiction, nonfiction, poetry, the choice is up to the writer. (She also has a poetry First 50)
Why I like it: it's a quick, fun way to stimulate creativity. Quick can be deceptive because I find I usually write more than 50 words and have to edit, re-edit, and edit again to get it down to exactly 50. Fun because the prompts are so varied and interesting. I can write my 50 words and be done in a few minutes, then read what others have posted. Painless!
Try it--you'll be hooked.