title: How to write custom template tags in Django easily?
body: <p>Writing template tags isn't easy in Django and involves lots of boilerplate code. 
  What is the least painful way to do it?</p>
  
  <ul>
  <li>Are there any libs for that?</li>
  <li>Are there any tricks that doesn't involve third-party apps?</li>
  <li>What is <em>your</em> way to do it?</li>
  </ul>
  
  <p>(I will make this post a community wiki once I figure how to do it.)</p>