Installing a gem locally is extremelly easy if you follow the steps below. I was recently in a situation where I had to upgrade a gem quickly to resolve a bug but the latest version of the gem located on http://gems.rubyforge.org was older than what was necessary. You need to locate the .gem file for the gem that needs to be installed and get a copy on the local server. In my case I happened to have a gem server that had ben installed but the web access was down at the moment so I SCP’d (secure copy) it to the local server and placed it in /usr/local/src.
Once you have the gem moved onto the local server issue the below command to install.