Circles are a key component of the Lean In project. Stanford University's Clayman Institute for Gender Research is Sheryl Sandberg's educational partner in the project. The circles are a place for women to "Surround yourself with people who believe in your dreams" while also tackling issues that women face in the workplace, together.
How to start a circle.
Circles are like book clubs with a purpose says Gina Bianchini of Leanin.org.
Find a co-moderator and then ask 10 friends and/or colleagues to join.
Then, go to http://leanin.org/start-a-circle/
The website provides step by step instructions for circle discussions and scheduling meetings.