Smart quotes in rich text fields? Is there a way to get the rich text field to automatically convert straight quotes to curly (smart) quotes? I'm not seeing anything on the redactorjs site or in the docs.
It turns out Smartdown should do the trick. It's a Craft plugin that adds MarkdownExtra and SmartyPants (the latter of which matters here) support to Twig.

SmartyPants is a rather ancient blogging plug-in from John Gruber for intelligently handling smart punctuation. Michel Fortin ran with it in the form of PHP SmartyPants, and most recently this Craft plugin by Experience.

Note: my first answer linked to a SmartyPants Craft filter by Experience that's apparently not finished. That one won't get you very far. :)