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 => true) do |example|
    name = example.metadata[:full_description].downcase.gsub(/\W+/, "_").split("_", 2).join("/")
    VCR.use_cassette(name, :record => :new_episodes) do
      example.call
    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