When you regularly make use of Cucumber's "show me the page" step (or let pages pop up as errors occur), the capybara-20120326132013.html files will clutter up your Rails root directory.

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To tell Capybara where it should save those files instead, put this into features/support/env.rb:

Capybara.save_and_open_page_path = 'tmp/capybara'