Several events are being planned for October 20. Instead of pinning each individual topic to the top of the list and overloading it, I'm going to list the topics pertaining to each of these events here.
In addition, there is a thread to discuss coordinating between the various events:
10/20 Joint Event Organization.
If I missed any events, send me a PM and I'll add them to the list.
(Topic is locked to direct any discussion of the events to their appropriate threads.)