So I signed up for a Google App Engine account a while ago, almost right after it's Python version was released last year. Of course, life prevented me from taking the time to learn Python, and so the learning curve prevented me from building or deploying anything.
Fast-forward to two weeks ago when Google released the Java API for the Google App Engine (GAE from here on out). Being a full-time Java programmer for the past 10 years, now we're running on all cylinders! I applied for a Java account on the day it was released and my Java GAE account was approved within 24 hours, but it took a few days for me to make some time to start writing some code. After about 8 hours of development I had my first working prototype of a web application running on the GAE.
My first GAE webapp is a service that connects to a set of social web sites that provide user names and profile pages for their users to see if a username you are interested is still available across those sites. My app is a called Handlecheck (handle in the sense of "username") and is live now at http://handlecheck.jaxzin.com.
This is also the first project I've open-sourced. I did a little reading on how to pick from the various open source licenses and settled on the GPLv3. I'm maintaining the source on Google Code.