Love Google docs and all that, but typographically it’s a little basic.
One of the things that bugs me is how it hyphenates (or rather, how it doesn’t bother with hyphenation at all). There is a workaround, though.
Here’s how you can add an en dash:
- in an open document, open the Tools > Preferences menu. This will display a list of characters that Google docs will replace with something else:

The Google docs preferences menu
- add a character (or set of characters) that you want to replace with an en dash (I chose two keyboard minus signs)
- add the character you’d like Google docs to display. Unfortunately, Google docs doesn’t recognise HTML entities (e.g. –); you could find an en dash and copy it
- paste your en dash into the Google docs preferences form:

An en dash. Yesterday.
- click OK. Google docs will now automatically replace two keyboard minus signs with an en dash:

An en (not an em) dash. Today.
You could, of course, add any other other characters via this menu.