I do a lot of work with CMS's, and find myself drawn to the user interface side of things. I like systems that allow complexity to arise through combinations of simple components. I am obsessed with distilling concepts down to their essence, streamlining interfaces (for end-users, designers, and developers), and extricating code from markup.
Some things of substance I've made that help designers and developers do their jobs better...
- Placepattern - image placeholder service for repeating backgrounds (a collaboration with Debra Kayes)
- HTML/CSS Reference Guide - introductory material for a class I teach at Columbia
- Minimal Responsive Grid - succinct guide to creating your own "responsive grid" in CSS
- Designer Content - a very popular addon for the Concrete5 CMS, allows designers to easily create editable structured content areas (kind of like ACF for Wordpress, or Matrix fields for EE/Craft)