I wish I could remember what Amnesia is...
One of my coworkers, Matt Hooper, recently released an open source project called Amnesia. The aim of Amnesia is to “transacts all changes to a website to facilitate automated UI testing”. Basically, you can run your tests and change and add data all day long and the changes, whether they come from the website or the tests themselves, will not last beyond the scope of the test. Pretty cool, huh?
The blog post where he announced it can be found here, and the source and documentation is hosted on Codeplex.