Crate is a developer tool to help package up your application as a custom static build of the ruby interpreter plus all dependent binary extensions. All the pure ruby code (the ruby application, the ruby stdlib, etc ) is packed into one or more SQLite databases. The final distributable pieces are a single executable and a few SQLite databases which can be then wrapped up appropriately as an OS X App; a self extracting executable for Windows; a shar archive, rpm or tarball for Unixes.