Argh! Someone has done something and something is ruined! Fortunately someone only changed records in CRM, and even better audit logging was enabled. You can now use the web service SDK to analyse changes that have occurred, you can then use this information to perform the opposite action and roll back changes.
Recently I needed to compare three different environments to see which entities were being audited. In the interests of making a boring task into an interesting task I decided to do this with an IronPython script.
I did this using Determination my IronPython/CRM 2011 tool, when given a connection string this will run through every entity in the environment letting you know which entity is being audited and which is not.