Hi everyone,
No stable version of GroupJive has yet been released. The status of the project is that it has been resting for a long time but we are now working hard on putting out a stable version. Until then, you will have to settle for the alphas (please try them out, we need testers).
The component can be found in the downloads section at groupjive.org, in the folder Testing versions. Every friday a new nightly build is released for testing. The modules are also available for download. The CB plugin is still under testing and will eventually be added to the downloads. For now it can be found in the forum, in the thread nzimas linked to.
The version in the forge is very old and not recommended for use. When a stable version is produced, it will be added to the forge.