While cruising around some links I came across Written? Kitten, aka the most adorable writing prompter on the internet. It's very simple, in that you type your words in the box provided. For every hundred words you write there, you get a (virtual) kitten, as you can see from my first try here:
I forgot to do a screen capture when I reached 100 words, so my screenshot actually shows my second kitten. This little online tool is oddly delightful, and while obviously all in good fun, might even help you bust through a writing block (unless you hate cats; then you might want to try a heartless unfeeling wretch prompter.) I think it would also be great for kids who are learning how to type or journal, or who might be slogging through written homework.