While not a traditional villain, grammatical errors are often haunting. So...today's post is dedicated to eradicating them.
There is a new-ish website I've been using with my classes that has been working well. While designed for teachers, I recommend that anyone who wants to brush up his/her grammar go to noredink.com and play around. You're given practice questions, immediate feedback, and tutorials for each question you answer. The best part? It's free.
You'll thank me for it later when you no longer fear the scary semi-colon goblins. :)