Use RSpec tags to add behavior around specs.

spec_helper.rb

# Add this to your spec_helper.rb
RSpec.configure do |config|
  config.treat_symbols_as_metadata_keys_with_true_values = true
  config.around(:each, :vcr) do |example|
    name = example.metadata[:full_description].downcase.gsub(/\W+/, "_").split("_", 2).join("/")
    begin
      VCR.use_cassette(name, :record => :new_episodes) do
        example.call
      end
    rescue Errno::ENAMETOOLONG
      name = Digest::MD5.hexdigest( name )
      retry
    end
  end
end

it "fetches google.com", :vcr do
  # this will automatically use VCR to save the response
  Net::HTTP.get(URI.parse("http://www.google.com/"))
end