I thought this post by Willy was interesting. It seems that the Visual Studio ALM Rangers are using a variation of Scrum that they are calling Ruck.
In the game of rugby, Ruck is a loose Scrum. The Rangers have adopted it as a term to define their unique and flexible process in order to handle distributed teams, part-time team members, and different time-zones.
For those of you who don’t know, the Rangers are a group of Microsoft internal and external folks (including MVPs) who build and deliver out-of-band solutions for missing features or guidance in Visual Studio.