Ruby apps can now be deployed to Google App Engine. We'll explore our latest development tools, and review the appengine APIs for Ruby. Developers also want to understand how to build apps using the App Engine datastore, our highly scalable persistence layer, so we'll discuss working with the datastore using the DataMapper API. We'll also introduce Duby, a new language with Ruby-inspired syntax, that compiles directly to Java bytecode. We'll show you why Duby is especially powerful for App Engine development.