Excel VBA Add-In for Quandl for Mac and Windows.
The Quandl Excel Add-In allows you to search through, find and download any of Quandl's millions of datasets directly from within Microsoft Excel. It's completely free; usage is unlimited and unrestricted.
http://www.quandl.com/help/excel
Excel add-in are stored in binary format so you need 3rd party tool to compare revisions (e.g. BeyondCompare).
CustomUIEditor
Source: http://openxmldeveloper.org/archive/2010/08/10/23248.aspx
This editor assists you in the process of adding Ribbon tabs, controls and icons. For more information follow the link above.
MIT License