ruby-build failed me, so I took matters into my own hands. Here's what worked
download and extract ruby 2.0.0p-195 to ~/.rbenv/src/ruby-2.0.0p195
mkdir $HOME/.rbenv/src
cd $HOME/.rbenv/src
wget ftp://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-p195.tar.gz
tar xzf ruby-2.0.0-p195.tar.gz