Free Ungroup All Add-in for Revit (Updated)

From the CASE Apps website...

A simple tool for ungrouping all groups of a specific kind (Detail and/or Model).

There's more information available on the CASE Apps website.

Update 5/8/2016: CASE and the CASE Apps website are no more but, courtesy of WeWork, the CASE Apps are now open source. They may be accessed on GitHub.