configurable_transactions.rb

def transactions(on_or_off=:on)
  if on_or_off == :off
    prepend_before { @transactions = :off }
  end

end

Spec::Runner.configure do |c|
  c.before(:each) do
    @transactions ||= :on
    if @transactions == :on
      # setup transactions
    end
  end

  c.after(:each) do
    if @transactions == :on
      # tear down transactions
    end
  end
end

describe "something" do
  transactions :off
  it "..." do
    # ....
  end
end