www.wtfconverter.appspot.com converts between common units of measurement (e.g. liters, seconds, etc) and silly units (e.g. butts, barns, etc.).
It was the first web application that I had developed using a web framework, in this case the webapp2 framework, on Google App Engine. This was two and a half years ago. Before that, I had developed everything from scratch, using PHP and MySQL for the backend.
This introduction to web frameworks intrigued me, and is what jump-started my journey into Ruby on Rails. Pushing local code to the Google App Engine production server and just having the site work blew my mind. Templating (the GAE tutorial taught how to use jinja2) was like magic, creating and managing dynamic content was so much easier.
I started out by following the GAE Python tutorial word for word, which walked the user through actually building a site. Then I developed my own little webapp that was a little more useful and wasn’t much more complicated than what I had learned in the tutorial. This is exactly how I learned Ruby on Rails too: I walked through the Rails tutorial, building a microblogging app along with the author. Then I built my own web app, Pomos the Pomodoro Technique timer, using what I learned from the tutorial. Pomos has since been deprecated, but here’s a screenshot:
Anyways, I learned a lot from following these tutorials where I actually developed something concrete, and then branching off to do my own thing. This is the heart of experiential learning, and what Sal Khan, founder of Khan Academy, talks about in his book One World Schoolhouse; when the student has ownership of his education by actually applying it, e.g. by building something, he is much more likely to enjoy learning new knowledge and skills. But reforming the current state education is a topic for another post.