I updated my blog from my own homebrew Rails application to Octopress, a blogging framework backed by the static site generator Jekyll. I first read about Octopress a couple of weeks ago on Hacker News. Although Octopress appealed to me on a technical level, in that it matched what I was already doing, having blog posts as files on disk, what really got me excited was the design of the default theme.
The default theme has a wonderful property: it flows. If you are using a full screen browser, try making the window narrower. First, the sidebar will be repositioned to the bottom. Then, if you make it even narrower, the top navigation will collapse into a pulldown navigation menu. This technique allows the same layout to look beautiful on a range of devices, from a PC down to a smartphone. The theme alone made me want to switch my blog to Octopress.
As developers, we appreciate good design. We also tend to suck at it. When an open source project comes along with good design, it sticks out from the crowd. So if you are looking to boost your open source project, team up with a designer.