From the department of fool me twice, shame on me. I ran into this issue on my laptop about a month ago and blanked on the solution when I had the same issue on my desktop.

All of my recent client work has used Ruby-1.9.3 so I decided to start using Ruby 2 for a couple of my personal projects in order to see what kinks I came across. I’m an RVM user so installing the new version was a simple matter of rvm install ruby 2.0.0-p247 (the latest patch when I made the jump).

The first kink came hard and fast when I wasn’t able to install any gems. A simple gem install bundler would result in this error:

WARNING:  Unable to pull data from 'https://rubygems.org/': SSL_connect returned=1 errno=0 state=SSLv3 read  
server certificate B: certificate verify failed (https://s3.amazonaws.com/production.s3.rubygems.org/specs.4.8.gz)

I spent a couple minutes doing some troubleshooting with no success, but then a search brought up a few different stack overflow posts that saved me from any (further) frustration. I actually had two problems- my rvm was woefully out of date and I needed to update the my SSL certificates.

Updating RVM

The RVM team couldn’t have made it any easier: rvm get stable

Checking & Updating SSL Certificates

Kudos again to the RVM team for making it simple:
Check the status of your certificates with: rvm osx-ssl-certs status
Update all of your certificates with: rvm osx-ssl-certs update all

Note: while just searching for links for this post I came across these exact same steps from Michal Papis- the release manager for RVM.