"The Scrum Master is responsible for ensuring Scrum is understood and enacted." [Scrum Guide by Jeff Sutherland and Ken Schwaber]
Scrum Master must master the scrum framework - this page contains resources for stuff we feel is important and useful for scrum masters in order to master.
It is not a complete or a final list, we try to keep it small enough to be digestible but not too small so that it is missing the major things. Your comments \ Suggestions are more than welcome.
The New New Product Development Game by Takeuchi and Nonaka - The article that inspired Scrum
The Scrum Guide by Jeff Sutherland and Ken Schwabber
The Big Idea - The Wise Leader by Takeuchi and Nonaka
The End of Software Engineering and the Start of Economic Cooperative Gaming - Alisrair Cockburn
10 quick and easy team building activity [Rishi Chowdhury]
Who is the Professional Scrum Master [Scrum.org]
21 Mandatory Tools for Distributed Agile Retrospectives [Luis Goncalves]
Tasty cupcakes - A website dedicated to sharing and learning about Agile games and activities.
Retro-o-mat - Probably the best online resource for Agile retrospectives, activities, format & structure, plus the awesome "draw a retrospective" feature.
The marshmallow challenge - The lesson in the marshmallow challenge is that we need to identify the assumptions in our project, and test them early and often.
The Scrum Master Checklist - The ultimate list of question to guide the SM's work
LeSS - Large Scaling Scrum
Videos- Michael James - Ken Schwabber - Uncle Bob Martin
Managing Serendipity - Dave Snowden