When Khan Academy initially released KaTeX 0.1.0 last year I was overjoyed. The performance comparison against MathJax was impressive and realistically the only reason MathJax has ever needed competition. For those interested in seeing the difference first hand, IntMath has a decent test suite.
A website for my research group outside of the bounds of our abysmal university web restrictions has been discussed for quite some time. It's genesis has only really started recently though, because I've had too many other things on my plate and no-one else has any decent web capability. Whilst I'd much prefer to use a simple static site tool or code something completely from scratch, the other members of my team really need something a bit more point and click. Plus, I'll be leaving the group soon so it's in their best interest to have a well rounded CMS interface with which they can administer the site.
Writing a thesis. Writing at home, writing at uni, at work, on planes, on machines half way across the planet with Swedish keyboards attached to them. The amount of computers that have my git repository cloned on it is either impressive or terrifying depending on how you look at it. One positive thing about my tree is that a good 90–95% of my ridiculous figure count has been built in Tikz / PGFPlots. Totally source control friendly, small and portable.