title: Design question: How would you design a recurring event system?
body: <p>If you were tasked to build an event scheduling system that supported recurring events, how would you do it?  How do you handle when an recurring event is removed?  How could you see when the future events will happen?</p>
  
  <p>i.e. When creating an event, you could pick "repeating daily" (or weekly, yearly, etc).</p>
  
  <p>One design per response please.  I'm used to Ruby/Rails, but use whatever you want to express the design.</p>
  
  <p>I was asked this at an interview, and couldn't come up with a really good response that I liked.</p>
  
  <p>Note: was <a href="https://stackoverflow.com/questions/85699/whats-the-best-way-to-model-recurring-events-in-a-calendar-application">already asked/answered here.</a> But I was hoping to get some more practical details, as detailed below:</p>
  
  <ul>
  <li>If it was necessary to be able to comment or otherwise add data to just one instance of the recurring event, how would that work?</li>
  <li>How would event changes and deletions work?</li>
  <li>How do you calculate when future events happen?</li>
  </ul>