compile a whole lot of ruby regex examples, with commentary on what's
going on. the few websites I've found, and books I've looked through
just touch on the basics with minimal examples and explanation, or are
specifically for perl/etc. a nice-looking and lengthy site could be
extremely helpful to a lot of people starting with ruby, I imagine.

- dealing with unicode?
- mingling literal " / \ etc, with their regex counterparts, in ways
that would be daunting for the inexperienced
- just generally "higher-level" regex, leave the "intro to regex" to
all the other places. that's easy enough to find.