This is not the greatest web 2.0 tool I have seen, because at first glance, it is not interactive. I love this website though because it provides so many writing prompts that I can use for classroom. I am always looking for creative writing prompts that would grab my middle school students. Though it's has not been updated since 2002, it provides an enormous selection of prompts to choose from. I also love the graphics/pictures that go with each prompt. The creator of the website tried to sort the prompts by most used, prompts about education, about reading, about personhood, and an option to randomly choose a prompt. Check it out! We are always looking for new ways to promote writing.
Check out the first prompt on the top of the page.