I've been trying to work on some of my grammar skills lately since I've been teaching ESL on Wednesday nights and since I want to start doing more writing. I've been exploring grammar sites on the Web and found one which seems to be fairly useful. It's a list of Common Errors in English. The error that I see the most that drives me insane is the misuse of the phrase "begs the question." If you start looking for it you'll see it misused very often.