A toolkit for creating metro-style WPF applications. Lots of goodness out-of-the box.
Read it here: http://mahapps.com/MahApps.Metro/
You can help keep the documentation up to date by submitting a pull request on the gh-pages branch of this repository. If you're unfamiliar with GitHub Pages, the help guides here are a good place to start.
If you've improved MahApps.Metro and think that other people would enjoy it, submit a pull request!
Drop in on the IRC room - #mametro on Freenode - if you want to ask a question.
Please read this page before submitting an issue.