The XRM Manipulation Library, previously the CRM Manipulation Library, is a set of custom workflow activities for Microsoft Dynamics® CRM to solve equations, date calculations, manipulates strings, perform regex (regular expression) formatting & matching, as well as SoundEx and Metaphone-Like codification.
"Microsoft Dynamics CRM’s built in workflow engine is pretty powerful, as anyone who’s worked with it for a while is aware. However, in our experience, a good customer quickly comes up with requirements that go beyond it’s built in capabilities, requiring custom activities. Engage is used to writing some basic activities to handle common problems, but now thanks the Carlton Colter of Microsoft, there’s a robust library of basic workflow activities up on codeplex for all CRM customers and partners." --Andrew Swerlick, Engage
For more information on how to use the manipulation library, look at the wiki.