I've recently been doing quite a bit of work with client-side templating, and I've really enjoyed working with Mustache. As part of Qotr development (which you can read about below), I put together some really basic templates for creating RSS feeds, by passing in simple hashes to a Mustache engine.
Well, besides the fact that my blog is obviously mine, it's an experiment with jekyll, markdown, and eventually I'm going to use it as a testbed for Coffeescript and SCSS experiments.
Qotr is a site where you can share quotes; inspired by sites such as bash.org and reddit, and many companies who keep their own internal quote boards on wikis, you can create your own board or post to a public board.
Drew Ditthardt and I built Alchemy Websockets, a .NET library that helps manage a huge number of websocket connections. Its architecture, pushed forward by Drew, allows it to handle multiple thousands of simulataneous connections on limited hardware. I helped build the interface layer, bugtest, and put together a basic client library for web browsers.