Semicolons Are Hilarious
Not really, but this comic by The Oatmeal does a hilarious and effective job of explaining how to use a semicolon. The comic is available for purchase as a poster, too.
Warning: many will find some of the other stuff on this website is offensive.
This link led me to a wonderful experience of humor as a tool of teaching grammar. I have been there for the last hour!
I can relate to an Oatmeal addiction, Mark. 🙂