I recently presented a talk on some good ways to use cryptography to improve your life, using some of my activism to illustrate its functionality. This is the essay form of that talk.
I've written some books as well. They cover human rights, intellectual property, social geometry, conceptual space, and globalization.
I develop open source software, too. It can help you monitor and secure networks and circumvent censorship.
I've also recorded some classical guitar music, calculated other songs, and played in a few bands.