When I was in college, I spent a summer developing an events calendar and new publishing system. It had lots of nifty, sophisticated features, like an in-browser image cropper, event reminders and downloadable iCal files. And it was a lot of work. The next summer, while working on an indie film studio's webiste, I came to the realization that I could have built the entire calendar app in a couple weeks using Drupal. I have been developing almost entirely in Drupal ever since.