I recently ran across three Facebook application generators that allow you to quickly generate a Facebook app from your existing Clearspring widgets, Widgetbox widgets, or Dapps (content feeds).

Clearspring's Facebook App Generator

Widgetbox's App Accelerator 

Dapper's Facebook App Maker 

Building a Widget inside an existing framework can be helpful for developers, as you can leverage existing APIs and distribution channels.

Thx to Mashable for the info. ;)