You have mentioned "Presentation" as one of meetup topics. Could you please tell me, have you ever made or heard a presentation of some scientific discoveries and break-troughs at your meetups? For example, someone could read an interesting article in a magazine, and tell about this topic at the meetup. Or just talk about his or her own speciality and science interests. For me it seems to be useful and interesting kind of activity to do at rationalists' meetings.