WHAT DEPREC IS
Deprec is a collection of automated recipes, written in ruby, for setting up production ready rails servers. The idea is, even if it takes longer to write a general recipe for your situation, rather than just doing it by hand, it's well worth the effort because you get a reliable and reproducible deployment that will work just as well even if it's 3am and a human would be liable to make mistakes with live webservers.
You also get the advantage of a further set of conventions, which means that other tools that you write can build on these conventions, in the same way that the conventions that we already have amongst rails and capistrano users benefit us when writing plugins and gems.
Deprec is designed to take a raw server, and set it up with current best practices for a production web server. Until recently this has meant Apache 2.2 for load balancing and static content, and Mongrel for serving rails. The default setup will soon be changed, with nginx replacing apache. A convention over configuration approach will be followed so Apache will be available to those who still wish to use it.
Version 1.x of deprec contains recipes specifically for default installations of Ubuntu 6.06 (server). Version 2.x of deprec (currently being worked on) will extract all ubuntu specific code to a plugin, alowing others to easily write thrid party plugins to get deprec working on other distros (and even OS's). deprec roadmap
Deprec also contains tasks which will allow it to be used on slightly non-standard ubuntu installations, such as those provided by slicehost.com.
Deprec has been tested on live VPS hosts with real production sites. It works for me, if it doesn't work for you, then it's easy to extend.
WHAT DEPREC ISN'T
Deprec isn't an attempt to solve all problems on all servers. I am solving my own deployment problems, and providing a general framework to help you solve yours. I'm currently working on deprec2.0 which will make it easy for others to write plugin support for other linux distributions.
