Rvm-view is a project mainly written in ..., it's free.
A tiny sinatra app to show you your rubies and gemsets
A tiny sinatra app that will delve into your .rvm folder and pull out details about what gems you have installed in your gemsets.
Clicking on a gemset link will display the hierarchy of root -> global -> gemset in one view so you can see all available gems.
Clone the repo and then run "rvm-view". A browser window should pop up showing your gems or you can browse to http://localhost:8070/