I work at Mint Digital, a creative company in south London.
Some of the things I do:
I set up and configured Mint's Hudson CI server. It runs the tests for all our client projects every time someone commits to GutHub. We use RVM, Git, Nginx, PostFix and more to keep us informed of our builds.
I also hack on Pyrite, our open source RubyGem that helps us automate UI testing of our apps in the browser. Pyrite makes Selenium less mental by providing a simple syntax and jQuery selectors. This makes selecting elements on the page via CSS a sane, reliable process. We even got picked up by Ruby5!
I work mostly with Ruby on Rails as a dev at Mint. We tend to build large, mostly social applications for a varity of clients. Sadly, all that is under wraps.