BitNami JRubyStack provides a fast, easy way to develop and deploy Ruby on Rails applications on a Java runtime using JRuby. It includes JRuby, Rails, Java, Tomcat, the GlassFish gem, MySQL, and Subversion. It supports Windows, Linux, and Mac OS X, so you can share the same Rails environment on multiple platforms.
The svnmailer is a tool that is usually called by a subversion hook to submit commit notifications in various ways (at the moment: mail via SMTP or a pipe to a sendmail like program, news via NNTP, or CIA live tracker notification via XML-RPC). It is derived from the original mailer.py distributed with subversion, but should be much more consistent, more extensible, and have many more features.
SVNChecker is a framework for Subversion pre-commit hooks in order to implement checks of the to-be-committed files before they are committed. For example, you can check for the code style or unit tests. The output of the checks can be send by mail, written to a file, or simply printed to the console.