Martini author here. Weird how it didn't show up in the golang-nuts search, here is a link to the announcement topic:
https://groups.google.com/forum/#!topic/golang-nuts/LubMauy6...
Martini is still young (less than a week) but the core is pretty fleshed out.
No boosting here (I don't even have that many twitter followers). I just put together a framework that doesn't step on your toes and people ate it up :)