Downloadify: Client-Side File Generation
http://downloadify.info/

Downloadify is a tiny JavaScript + Flash library that enables the generation and saving of files on the fly, in the browser, without server interaction.

Downloadify is a tiny JavaScript + Flash library that enables the generation and saving of files on the fly, in the browser, without server interaction. * Overview * Download Overview Web applications that allow you to generate vCards, color palettes, custom code, etc would benefit from using this library. In addition to increasing speed (no round trip to the server) this solution can reduce the database and server load of existing web applications. This is not a library to ‘force download’ a file from a server. It does not interact with a server at all.

This could be interesting...