Essentially a reversed word counter: you input a target number (of words, paragraphs, sentences, pages etc.), and it tells you how much you've got left to write (i.e. "200 words to go").
Alternatively, it could tell you what proportion of the necessary you've done (i.e. "20% complete").
Perhaps even implement stages in the target (i.e. "200 words to go, but in 50 you can have a snack")?
EDIT: Changed a redundant "have" into a "can" (see how I used the opportunity to up the word count by 21?).-- dbmag9, Dec 30 2007 M$ Word (or Open Office Write) > Tools > Word Count > Subtract.
What do you want, the f%*@ing paper clip dancing around and saying "you are now half done with a 500 word essay, can I now cause a memory leak which will cause you too loose all you work?"-- MisterQED, Dec 31 2007 For students, there could be a "grade" indicator in the status bar. It starts at "F" and as you add more and more distinct words and paragraphs, it improves to D-, D, D+, etc... up to A+-- phundug, Dec 31 2007 [MisterQED]: Really? That doesn't work with my computer (Word XP), or with any other version of Word that I've seen. No, I don't want the paperclip dancing, just a display similar to the current word count display, that displays a "words to go" count instead.-- dbmag9, Jan 01 2008 random, halfbakery