Calypso is a full clone of the Django Template Language that helps developers separates the presentational and logic concerns of the application. It offers template inheritance, pluggable tags and filters, and can be easily integrated into the Zend Framework

The most powerful part of the Calypso system is the template inheritance. It allows you to build up a skeleton of templates that can be used for the entire site with blocks and areas that any other part of the application can easily override.