Most of my hobby projects are available at my skunkworks on Sourcehut. These are admittedly fairly small projects, but include:

• hsh, a Markdown-oriented note taking and todo-list app initially modeled after (and initially compatible with) nb;
• dortune, a silly example of using Deno’s URL-based imports to have a no-install fortune tool;
• egabbai, a tool for printing synagogue aliyah cards; and of course,
• my yearly Advent of Code solutions

Additionally, I’ve been involved to varying degrees on two larger projects in the past:

• Factor, a modern postfix language (think a high-level, new take on Forth); and
• Mercurial, “the other DVCS”, which is unfortunately so amazingly dead that both Facebook and Google are busily adopting it as their One True SCM even as we speak

You can see a full list of everything I’m actively working on in my by visiting my sourcehut account.

On the closed-source front, the biggest project I worked on in the past was at Fog Creek, where I worked heavily on Kiln, a cutting-edge DVCS hosting solution initially based on Mercurial, and later allowing each member of a team to make their own choice between Mercurial and Git on a commit-by-commit basis—the only tool to provide such functionality. Way back at the beginning of my career, I worked on Fog Creek Copilot, a remote assistance solution for micro-ISVs.