Sign in by going to the website http://www.meetup.com/BitcoinWednesday/ there is room for about 200 people and allthough room is half full most of the times, I've heard that while I was building Liberland more and more people started to show up, so be sure to sign up. I'll be there, let me know when you are too!
This is a monthly event, every forst wednesday of the month.