In this download area, you will be able to download the distribution (binary and source), the Windows installer (for some of the versions) and the documentation for Groovy. You may also be interested in third-party packages, such as the Ubuntu-based PPA packages.
Groovy 2.1 is the latest official major version of Groovy
In addition to the stable and milestone releases you can find intermediate SNAPSHOT releases at the codehaus snapshot maven repository.
The web page http://freshgroovy.com/groovy/ provides a PPA based Ubuntu package repository. The packages there are updated on a regular base, but not 100% in sync with our releases. New packages are announced on twitter at @FreshGroovy. For instructions on how to use the repository, please visit the website.
Other ways to get Groovy
You can use the Groovy Enviroment Management Tool if you want to maintain and switch easily between different versions of Groovy.