punctuation is hot.

For those of you who are equally concerned about the misuse of the em/en dash, Punct'd posters from Neenah Paper.

En dash
The en dash is used to indicate a range of just about anything including dates, numbers (32–24–36), game scores, and pages in any sort of document. It is also used instead of the word "to" to indicate a connection between things, including geographic reference and routes (such as the New York–Miami flight).

Em dash
The em dash is about twice the width of the en dash and is typically used to indicate a sudden break or an abrupt change in thought ("I met you at the beach last—what was your name again?"). Grammatically it is stronger than a comma but weaker than a period and is often used as a replacement to the parentheses in setting off supportive text. It is also used to indicate an open range, such as from a given date with no end yet (as in "Todd St. John [1969—] designed this poster.").