The title says it all. Basically, my idea is to create a thread where each user can submit a paragraph or two of text. This text may be crafted specifically for the thread, or it may be lifted from the users other written work. An example that comes to mind would be an excerpt from an RP in which the user is currently involved. Another user could then come along and critique the submitted text of the former. Give tips or even full blown explanations regarding the quality of the grammar and how to improve. 

Feel free to critique anything I've written so far. After all, no matter how good we may think we are, we could all use some improvement.