I was the organizer of the NYC rationalist community until I moved to the Bay Area. I wrote a case study about the community, so that I could share the lessons I learned with other potential organizers and community members. This prompted the creation of several dozen meetups around the world. You can read about it here.
I also wrote a post about a wildly successful exercise we did at one of the NYC meetups. We divided into groups of at most four people, picked 12 cognitive biases, and spent 5 minutes on each one discussing how to recognize, correct and utilize them. I wrote down everyone's answers and compiled them into a post here.
I gave a speech on rationality and self-improvement to the 20 Under 20 fellows, describing what rationality is and how to apply it to your life. You can watch the entire speech here.
Enjoy!