Ask HN: How can you teach practical regex to normals?

I'd like to teach regular expressions to some friends who do a lot of clerical work, but I'm at a loss with where to start. I want to avoid as much of the theoretical stuff as possible & get them to a practical level as quickly as I can.

I haven't really found anything geared toward teaching regex to kids or non-coders. Anyone have any experience with this or tips for how to approach the problem? What about unique ways to visualize regex?