Arquillian has an modern, HTML5-based website baked with Awestruct. The site uses more than a dozen Awestruct extensions, many custom made. It introduces a release extension, which builds on the
Posts extension to dynamically create a post for each software release. It also has an extension that creates module and contributor pages by analyzing the project's source repositories.
The site leverages REST APIs heavily to pull in data, some of which is collected during site baking and the rest retrieved on page load using JSON-P and jQuery plugins.
The site's theme is built on Bootstrap. It's arranged on a 12-column fixed grid and has a responsive layout. The CSS classes are semantic, achieved by extending Bootstrap classes and mixing in custom styles using SASS.
The Ceylon site has a nice custom look.
OptaPlanner uses a default look, twitter bootstrap, tango project icons and a minimalistic header and footer. All links are relative (thanks to the Relative extension) to allow offline testing.