Stubs is a lightweight framework for test stubs and detours in .NET that is entirely based on delegates, type safe, Refactorable, debuggable and source code generated.
Stubs also allows to replace  any .NET method with a user-defined delegate, including non-virtual/static methods in sealed types. Stubs is fully integrated into Pex , an automated white box test generation tool for .NET.
http://research.microsoft.com/en-us/projects/stubs/

Speaker: Jonathan ‘Peli’ de Halleux
Peli is a Senior Research Software Design Engineer in the Foundations for Software Engineering (FSE) group at Microsoft Research in Redmond, USA, where he has been since October 2006 working the Pex project. From 2004 to 2006, he worked in the Common Language Runtime (CLR) as a Software Design Engineer in Test (SDE/T) in charge of the Just In Time compiler. Before joining Microsoft, he earned a PhD in Applied Mathematics from the Catholic University of Louvain. Earlier, he developed the unit testing framework MbUnit.