You may enjoy the EATS SHOOTS & LEAVES Punctuation Game. It may have been posted here before, but I'm not in the mood to look it up.

That's a fun game - although the last two (I think) in the 'comma' section I felt were subjective, and an argument could be made for or against the comma, depending on the speed, rhythm and tone of voice at which the author wanted each phrase to be read. That's how I tend to think of commas outside of the usual rules - if I want the reader to pause, I insert one; if I want the words to run into one another I won't.

That's not very eloquent because I'm tired. I hope you all get what I'm trying to say.

Awww, Shu, you're always in a good mood to me, and Cat, you're always eloquent!

I didn't put an apostrophe in "four yards worth," though I can see that I was wrong. Darn...it had to be the apostrophe!