There was a piece in the Times a few days ago on semicolons, and I thought it might be useful for class discussions. The Times came out from behind its paywall a while ago, so its site is useful again (link pasted below).
http://www.nytimes.com/2008/02/18/nyregion/18semicolon.html?em&ex=1203742800&en=2f33d339a23e01ab&ei=5087%0A