pow isn't written in ruby, but javascript. So it might be installable from npm soon. If you `git clone git://github.com/37signals/pow.git`, you can install it

pow isn't written in ruby, but javascript. So it might be installable from npm soon. If you `git clone git://github.com/37signals/pow.git`, you can install it from source with `npm install -g` (requires npm 1.0)