I was the first (of what is now the "all golds XML club") to hold all of these: the gold badge in XSLT, the gold badge in XML and the gold badge in XPath.

Some of the more interesting things I've been doing can be found via these links:

Training course on "XSLT 2.0 and 1.0 Foundations" (12 modules, 8hrs 45minutes)

Training course on "The Evolution of XPath: What’s New in XPath 3.0" (7 modules, 4hrs 30 minutes)

Training course on "What's New in XSLT 3.0: Part 1" (8 modules, 5hrs 30 minutes)

     my Finger Tree implementation in C#
     My Original XPath Visualizer hosted by Lars Huttar
     the Extreme Markup Conf. presentation on FXSL 2.0
     My Balisage 2013 paper "Programming in XPath 3.0",
      and the PPT presentation
     My Blog
     Follow me on Twitter