At OpenOakland our format is roughly, 5 minute presentation about what OpenOakland is, do a quick round of introductions (of projects, and people), and then announcements for the room.
We try to break out into groups to work about 15-20 minutes from the start of the meeting. Our goals are the same as yours - a balance between helpful for the newcomers without being too repetitive for the oldcomers.
Here is the intro presentation we use:
Most of the good bits happen during a subsequent onboarding presentation. One of us (usually @ramymik) takes the time to meet each newcomer in more depth and give them advice on how to engage.
For in-person meet-ups, we usually have about 30 minutes before we start to eat, mingle, network. We usually use this time to welcome new folks and explain the brigade / Code for America relationship and mission. Our agenda usually includes:
Welcome / Code of Conduct
Introductions (we go around the room and everyone introduces themselves)
After introductions, I’ll give a 2-4 minute of what open cleveland if there’s multiple new attendees (which are most hack nights) and I had been concerned that it’s not really useful for the regulars but after hearing from the regulars, they see that the short intro is worth doing for the new attendees.
I also purposely try to get there 15-20 minutes before the meeting starts and personally chat up each of the new attendees and find out what they’re interested in; why did they come; what did they hope to get out of this event. This is also helpful since we don’t have any permanent sign-age at our meeting space and new attendees can find out where to go at our venue