Hello, Android! It's Duby!
This is the most basic example of how you can build Android app using Duby. For stuff that goes beyond the build process, please see Garrett.
Copy local.properties.example to local.properties and edit it to point to your SDK. If you're not targeting Android 2.1, you might need to edit default.properties too.
Then you should be set to do "ant debug", and an apk file should be generated in the bin/ directory.