Sharepoint and MVC

Recently a client asked me if I have experience in SharePoint combined with MVC. My response was "no", but  the question kept running through my mind... So I decided to do some testing and investigate the possibilities of SharePoint and MVC. First of all I want to know why one would use MVC instead of webforms, MVP or MVVM? 
Since this is a lot of material , I will explain in as series of a few posts what the different design patterns are.  In the last post I will sum up the pros and cons of each pattern. I will also answer the question "is it possible to use SharePoint in an MVC pattern"