GreyMatter is a FlatPress theme I've been working on during the summer. It's basically the FlatPress version of a theme available for the Jekyll blog engine.
It feels pretty modern and actual compared to most of the themes that can be found for FlatPress. It has nice category tags, and a nice, clean design.
This is v0.1, as it's not entirely completed: GreyMatter is just barely responsive. It renders okay on a small screen, but has some issues that prevents me from releasing a version 1.0 right away. If you are interested to contribute, the code is on GitHub: GreyMatter | GitHub.
Log on the Official FlatPress Forum if you need support or have any question. I'll be happy to help you out.