This is a small selection of my open source work; see my GitHub page for a longer list.
I haven't had a chance to put together a list of the commercial projects that I've worked on yet; if you're interested feel free to drop me a line.
Nesta is a Ruby CMS for developers and designers, built using the Sinatra web framework. It's especially popular with people who like to write their content in Markdown or Textile (though you can create your pages in Haml or HTML if you really need the flexibility).
For more information head over to nestacms.com.
python-satisfaction is a Python library that wraps the Get Satisfaction API. Get Satisfaction are linking to python-satisfaction from their API library page.
Checkout the code on GitHub.
Basecamp Safari Extension
The layout of a Basecamp message that contains very long URLs is suboptimal at best. I've written a Safari extension that modifies the way that such messages are displayed , and released it as a Safari extension.
The source code is available on GitHub. Also available as a user script for Fluid.app.
More open source...
There's more. See GitHub or SourceForge.