This article shows how you can install Ruby on Rails (RoR) and integrate it in Apache2 on a Debian Etch system (including a short section at the end showing how to use RoR in a web site created with ISPConfig).
Read it at howtoforge
Ruby on Rails is a web application framework which is rapidly gaining popularity among web programmers. It aims to increase the speed and ease with which database-driven web sites can be created and offers skeleton code frameworks (scaffolding) from the outset. Applications using the RoR framework are developed using the Model-View-Controller design pattern.