Some time ago we read Sticky Church by Larry Osborne, and one of the lessons we took away was this: that new people do best in new groups. People stick better in groups when they get into a group with other new people, rather than trying to break into existing circles. We had been trying to add people to existing groups, and felt like it wasn't working.
So we went to the idea that we would have quarterly connection events, where we would create new groups. We had resisted this for some time because we never had enough leaders ready to go. To counter this, we developed a mentor-coach, where staff, coaches or existing leaders would mentor a new group for four weeks, as a new leader for the group was identified and trained. This has been the single biggest improvement we've made in our connection method. We still raise up leaders the old fashioned way, but by using a mentor-coach we can create groups on demand.
Our connection events run like this: The room is set up with tables designated for the night of the week, and as people come in they are directed to those tables, that are pre-seeded with a new leader or a mentor-coach. The leader engages them in some ice breakers just to get people talking and become familiar with others.
After 15 or 20 minutes, we stop the discussion, and direct people to get up and go to another table, where they get to know another different group of people, using the same ice breakers. After another 15 or 20 minutes, we again stop the proceedings and direct people to go to the table that you would like to be in a small group with. By this time, people have picked out others that they want to hang out with, and those that they don't want to hang out with. We have our leaders and mentor-coaches now fill out their rosters. In many cases at this time, the event is done, and people don't want to leave!
What about people who can't make the connection event? After the event, we then get our new groups up on our group locator on our web site, where new people can join the group in the first three weeks, after that, the groups are closed on the web. Then we handle new people on the staff level, knowing what groups are really good at assimilating new members.