Gem in a box is a simple sinatra app to allow you to host your own in-house gems.

It has no security, or authentication so you should handle this yourself.

gem install geminabox

Create a config.ru as follows:

require "rubygems"
require "geminabox"

Geminabox.data = "/var/geminabox-data" # …or wherever
run Geminabox

And finally, hook up the config.ru as you normally would (passenger, thin, unicorn, whatever floats you boat).

gem install geminabox

gem inabox pkg/my-awesome-gem-1.0.gem

Simples!