Bundler: Fatal error and 'no such file to load -- net/https'

Today, I ran into trouble on a fairly fresh installed VM, running Ubuntu. I tried to bundle install and got this stacktrace:

Fetching gem metadata from https://rubygems.org/.Unfortunately, a fatal error has occurred. Please see the Bundler 
troubleshooting documentation at http://bit.ly/bundler-issues. Thanks! 
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require': no such file to load -- net/https (LoadError)
	from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
	from /usr/lib/ruby/gems/1.8/gems/bundler-1.1.4/lib/bundler/vendor/net/http/persistent.rb:447:in `ssl'
	from /usr/lib/ruby/gems/1.8/gems/bundler-1.1.4/lib/bundler/vendor/net/http/persistent.rb:216:in `connection_for'
	from /usr/lib/ruby/gems/1.8/gems/bundler-1.1.4/lib/bundler/vendor/net/http/persistent.rb:358:in `request'

Obviously, bundler couldn't connect to rubygems.org. Check if you have the Ruby bindings for OpenSSL installed. On Ubuntu, it is the libopenssl-ruby package.