Konstrukt is a project mainly written in PHP, based on the MIT license.
Konstrukt fits a toolchain around such tools as SASS, Coffeescript and Sprockets. It's basically a very lightweight build tool for web apps.
Using Konstrukt, you can make PHP build scripts that call the underlying tools using an abstract interface. You may also configure your custom build script to automatically listen for changes in the underlying files.
chmod +x build.php
./build.php
Konstrukt is created and maintained by ExtendD (www.extendd.nl).