I've been working hard the past 2.5 years teaching a bunch of new courses and improving old courses. One of the things that's helped a ton is converting hand-written lecture notes into LaTeX.
Many years ago, I started working on a style file to add a bunch of commands for lecture notes. Most important, I created a question command to facilitate Socratic-style lectures. I later modified this so that I could set a flag indicating that the output was for students. Then it would hide the answers to those questions. I started posting these versions online for students.
I've been adding stuff to this, but recently really wished I could add exercises that would put all the answers in an appendix, but hide those answers in the student version. I recently discovered the exercise package (thanks, Stack Exchange) which can do this automatically. Using that, I updated my style file, and recently posted the code on GitHub. (If you're not familiar with GitHub, I made my own landing page.)
I find that it's really convenient to teach from the pdfs on a tablet, and it saves me tons of paper. The only issue is that it's a bit more difficult to make notes on the pdfs than with a regular pen and paper.
The Best Writing on Mathematics 2016
17 hours ago