Kohana PHP is an HMVC PHP5 framework that provides a rich set of components for quickly building robust and dynamic web applications. It is a relatively lesser known framework when compared to other, such as CakePHP

CakePHP

CakePHP is an open source web application framework for producing web applications. It is written in PHP, modeled after the concepts of Ruby on Rails, and distributed under the MIT License.-History:...

 or CodeIgniter, and has a small "strong but elite" community. It is commonly compared to Yii Framework in terms of speed and other features, but offers some advantages (and disadvantages) to Yii.