Here's a guide to the programs I've written and put on GitHub. I've excluded repositories that I don't think will be generally useful, such as task code for my research and forks with trivial changes.
My favorite programming language is Hy, a Lisp dialect for Python, and I'm the maintainer of its compiler. I also use a lot of Python (for situations in which Hy is too niche) and R (for my job). In the days before my involvement in Hy, I mostly used Perl. I no longer write new programs in Perl that are longer than one-liners, but I have a good number of unreleased Perl programs that I continue to maintain for personal use.
I only release software under free licenses, usually the GPL.
Daylight: Software for doing open-notebook science in Org mode. I use it for all sorts of documents, including much of this website.
Citematic: Scrapes and formats citations to journal articles and books. The formatting code is used by Daylight for bibliographies, but the scraping code is undermaintained.
Artiruno: A program to help you make decisions with verbal decision analysis.
Pairmemo: An R package for flexible on-disk function memoization.
ThoughtForms: A Python library for simple JavaScript-free Web surveys and experiments via WSGI. (Tversky and SchizoidPy are earlier iterations of similar ideas.)