Rod has an interesting post about where and when you should use apostrophes (arguably the most misused punctuation). If you were ever curious, and want a good laugh while being educated, you should read “Eats, Shoots and Leaves”. This book contains hundreds of illustrations of where you should and shouldn’t use a range of punctuation and IMHO should be a core teaching requirement for all high schools!
. " , ‘ ; ! – ? _ Are all examples of …… Often Misused Punctuation