rejectmail-rails
Rejectmail was a Rails application written in 2006 to address the problem of spam resulting from signing up for things online. The original application was written in PHP and this was intended to be a port to Rails.
The service provided a public email inbox. Users could make up any email address like xyz123@rejectmail.com to use when signing up for things online. To check the inbox you would visit rejectmail.com and enter that made up email address. The ability to send from an email address was also added.